Copyright N°
COPYRIGHT DEPOSIT:
Te
iV’
SUCCESSFUL
INCUBATION
A WORKING MANUAL FOR
LARGE HATCHING PLANTS
ar apse
By P. COOK
PROPRIETOR OF THE MAMMOTH HATCHERY
LOS ANGELES CAL,
PRICE, $1.00 NET
PUBLISHED BY THE
WEIMAR PRESS
8015 8. MAIN ST., LOS ANGELES,CAL.
Copyright, 1911
By P. Cook.
€ CLA280782
PREFACE
This little book gives our experiences in hatching
conducted for about six years. It is the story of our
investigations, how we have finally stumbled on to the
right way to hatch chicks. It is hoped it will save many
the heart-rending experiences we have gone through.
When you once know how, it is simple enough to hatch
chicks, but it is not always easy to find out the simple
way.
We also hope that there will be no disappointment
to our readers. It seems that most poultry books are
written by persons sitting by a cosy fire spinning theo-
ries that are utterly impracticable. This book is based
on actual hatchery work and every effort has been made
not to mislead any one or make claims unsupported by
actual facts.
But there is still room for improvement and we shall
be glad to hear from our readers if difficulties persist.
All letters to me should be addressed to the publishers
of the book, and they will be forwarded.
The price of the book may seem high to many per-
sons, but it costs a great deal to publish a book. It is
not the paper it is printed on, but the advertising that
costs, and it is more than doubtful whether the pub-
lishers will ever be adequately paid for it even at its
high price. It contains real information, that will be
worth tenfold its price to any reader even the first year
he uses an incubator.
Moreover, it must be remembered that all the inven-
tions of this book are given free to the public, there are
no patents on any of them. Everybody is at liberty to
use what he likes. The proceeds from the book is the
only remuneration the author receives.
P. COOK.
Los Angeles, Cal., Jan. 1, 1911.
(92ed JXON] 29098 UOQALISo(] 40 J)
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DESCRIPTION OF P. COOK’S INCUBATOR
(See Diagram on Preceding Page)
Fig. 1. a, jacket enclosing boiler. This communi-
cates with the outer air around its lower rim. The air
thus heated by the sides of the boiler passes into the
upper compartment of the incubator through the open-
ing e, during incubation there is no other ventilation. It
will be seen at once that this method procures a great
deal of superheated air, which helps to take care of the
evaporation from the eggs without unduly increasing the
humidity of the egg-chamber. b, small tubes through
which heat from the lamp, y, passes through the boiler, c,
when the damper of the regulator is down. When
damper is raised, the heat passes directly from the lamp
through the large centre tube, 0, without heating it, n,
‘is a collar or rim compelling the heat from the lamp
to ascend through small tubes, instead of dissipating be-
low the boiler; f, portion of return pipe from incubator;
d, portion of outflow pipe or coil entering incubator; h,
thin muslin diaphragm separating upper and lower com-
partment of incubator, preventing any draft from air en-
tering at e; k, egg tray; i, nursery; m, incubator legs;
p, ventilating tube, used to dry off chicks after hatch-
ing. Kept closed during incubation.
Fig. IJ]. r, incubator; s, drawer containing nursery
and egg tray; t, stick on which drawer rests when pulled
out.
Note.—All the experiments and successful hatches de-
scribed in this book have been made with machines con-
forming strictly to this type. We have so far found this
the most successful type, and used it equally well with
hot air as with hot water heating.
INCUBATOR INSTRUMENTS
P. Cook's Carbonic Acid Gas Test, complete set of all neces-
sary instruments, $5.00
P. Cook's Hygrometer, continuous reading, $3.00
P. Cook's Simplified Hygrometer $1.00 postpaid
(No one using an incubator should be without at least the
Simplified Hygrometer. The other instruments are for
large hatcheries.)
For sale by P. COOK, 3017 S. Main St., Los Angeles, Cal.
Note to page 21---No carbonic acid gas is given off by the
ody of the hen. We have made many tests to that
effect. All that is found under her comes from the
respiration of the embryo.
SUCCESSFUL INCUBATION
SOME EXPERIENCES WITH INCUBATORS.
Some of the strangest experiences take place with in-
cubators. We have had our share of them. The
very first incubator we bought happened to be a good
one, and we had reasonably good hatches out of it, yet
a considerable proportion of the chicks died in the shells.
We supposed that with more experience we would be
able to get better hatches, but the contrary proved to
be the case. After two hatches we moved this incubator
to another building, and we had nothing but poor hatches
from it in spite of the best of our care, so we gave up
that kind of an incubator. Then we heard of one
that was producing very good hatches through an ac-
quaintance, and we invested in that make, but it would
not hatch for us in any way at all. We tried it six or
seven times, and lost practically every hatch. Then it
was moved to another room, and as we were badly need-
ing an incubator to take care of some surplus eggs, we
decided to run it once more, and the machine has given
very good hatches to the present date, standing in this
one place.
In the meantime we also built different types of in-
cubators of our own to find out, if possible, the difficulties
in incubation, and though we constructed over thirty
different types of machines, and tried almost every con-
ceivable method we did not seem to make any particu-
lar headway. It was always the same old story, some-
times a very good hatch, and then a number of very bad
ones. We tried it three times with one very popular
make of incubator, and in each hatch as many chicks
were dead in their shells as those that succeeded in get-
ting out. We sold the machine in disgust. The man
who bought it from us moved it to his house, and the
machine hatched every fertile egg, although he had never
run an incubator before.
We had another machine which we built ourselves
that gave a very remarkable hatch, and we hoped we
were nearing the goal. We moved it to another room
in our hatchery, and it would not hatch there at all.
And more perplexing still was another case of a ma-
chine holding about 1000 eggs. It had four drawers,
and the two drawers in the rear end of the machine
always hatched very well. The two drawers in the other
end of the machine, while the temperature was the same
throughout, never hatched at all, i. e., most of the chicks
died in the shell, or were cripples, though it was im-
possible to discover any difference in the machine.
Another peculiar case we had was this: Someone
brought us some eggs on which a hen had set for four
7
days, and then died on the nest. It was about 18 hours
after the hen was dead that the eggs were brought to us,
and the eggs were stone cold when they arrived. We
placed them in an incubator with 300 eggs in it, which
had been set just about the same time. At the time of
hatching we secured nine strong, lively chicks from the
eggs the hen had set on, and there was only one egg
which was fertile that failed to hatch of the hen’s
clutch, but the 300 in the incubator practically did not
hatch at all, i. e., there were about fifty miserable chicks
that got out. The rest did not get out of the shell at all.
We have tried a great variety of different makes of
machines, and we have had the same story with all of
them. Sometimes they hatch very well, and sometimes
they do not hatch at all. Most of the time there are
more dead chicks in the shell than there ought to be
with all of them. Some machines are far better built
than others, but even the poorest made machines have
given us just as good hatches, as the most expensive
ones.
The glowing testimonials which all the incubator man-
ufacturers send out are probably genuine, as we could
duplicate most of them once in a while. Nearly every
make of machine we have seen sometimes give as good
hatches as claimed, but there is always against the
one success a woeful lot of failures. Of course, if eggs
are exceptionally strong and vigorous in fertility, they
will perhaps hatch under almost any conditions, but
the great necessity for poultry raising is to get an in-
cubator that will hatch nearly as well as the hen, and
in all our experiences with the hens we have found
that, barring accident, she succeeds in hatching practi-
cally all the fertile eggs. We soon became convinced,
of course, that something must be wrong with the in-
cubator, but the harder we tried to find out the farther
we seemed to be from the goal.
It is easy to build a new incubator, and build one
that one thinks is a great improvement. Ninety-nine
times out of one hundred it will be found, however,
that the new machine is worse than the old one. It is
needless to rehearse the whole history of our experiences.
I simply mention these things to show that in the way
incubators have been constructed hitherto some vital
things have been lacking, and if anyone has experiences
similar to these, he must remember that every other
poultry man is apt to find such happenings some time
or other. It is true, some poultrymen have been singu-
larly fortunate in having almost always good hatches,
and others have been singularly unfortunate, in al-
most always having very poor hatches. However, we
think that, in the following pages we describe a method
which will enable anyone to secure hatches nearly as
good as those the hen produces.
So far as we know we have good reason to believe that
the essential principles of incubation have been discov-
ered, and the only thing that remains to be done is to
8
reach a greater perfection of our method. At any rate,
the only way to discover the right method is by un-
ceasing experiments, and we shall be very glad if persons
who follow our method will report to us the success, or
lack of success, which they have. We hope for the heart-
iest co-operation in this respect, as the first principle
in successful poultry keeping, is the successful hatching
of strong, vigorous chicks.
It is certain that in an incubator where fifty per cent
of the chicks die in the shell, the chicks that actually do
get out have not been incubated under desirable condi-
tions, and must have suffered considerable, which means
that they are handicapped from the first.
It is an unfortunate thing that it is almost next to
impossible to have people willing to acknowledge their
failures in hatching. Every body seems to think it a
disgrace to acknowledge the unsuccessful hatching of his
eggs. It is time that there be a little more honesty
among poultry men in this respect, and if anyone has
discovered a successful way of hatching he should be
willing to let his neighbors know it.
We believe that we have made very important discov-
eries and therefore publish this little volume, but we de-
sire to have it taken as an incentive to more careful ex-
periments, much rather than as an entire solution of the
problem.
The most careful methods are necessary for this in-
vestigation, and much patience must be exercised, but
‘the fact that eyery once in a while an incubator pro_
duces perfect hatches shows beyond a doubt that the
goal of unfailing success is attainable, and if we are
patient enough and work hard enough we shall finally
wrest from nature her secrets.
HOT WATER OR HOT AIR INCUBATORS.
We have used very extensively in our tests, both hot
water and hot air incubators, and so far as the hatching
of eggs is concerned, it makes not the slightest difference
which is used, providing it is constructed properly.
Manufacturers of hot water machines should see to it
that their hot water tanks are well made, and especially
should avoid any combination of galvanized iron with
brass or copper, as these are sure to leak in a very short
time, on account of electrolysis.
We should advise, however, for all small machines, the
use of hot air, as we have found in our experience that
it gives much less trouble. If once such incubators are
built right, they last practically a life time. The heat
is not as even in a hot air machine, as it can be made in
a hot water machine. But a little unevenness of heat
seems to be of no importance. The hot-air machine is
less trouble to take care of than the hot water machine.
However, the hot air machines can hardly be built suc-
cessfully to take care of more than 500 eggs. If larger
machines are to be used, hot water is required.
9
We have also experimented with a great many differ-
ent boiler systems, but find a copper boiler with a large
tube through the center, and a series of small tubes run-
ning parallel with it between the large center tube and
the sides of the boiler, to be the most successful. The
damper is placed over the large center tube connected
with a thermostat. When the damper rises, the heat
from the lamp or gas flame passes directly through the
center tube without heating any water in the _ boiler.
When the damper is closed the heat passes up the center
tube and returns through the smaller tubes before find-
ing an outlet, thus giving an immense heat surface.
The requirements for incubator boilers are that they
should have an immense heating surface when the dam-
per is closed, and when the damper is open none, or at
least only a very small amount of heat should pass to
the boiler.
The best circulating system we have found to be
wrought iron pipe connected in the ordinary way to
the boiler, but the outflow pipes should be connected
to the top of the boiler, and the return flow should enter
the bottom of the boiler. The boiler always must be
placed somewhat lower than the outflow pipes. In our
practice we place the outflow pipes at the top of the
boiler, and let them rise gradually about one inch, or
sometimes two inches to the extreme back of the ma-
chine, and then let the return pipe have a fall of about
two inches through the length of the incubator, and then
let it pass down to the bottom of he boiler. It does
not make any difference how far the highest point of the
pipe is from the boiler, as hot water will rise to the top,
but there must be an even fall from the highest point
to the return, in order to insure good circulation.
In hot air machines the difficulty is to spread out the
heat toward the sides. There are several ways which
seem to do the work equally well, and a number of differ-
ent systems are in use on the incubators on the market.
We cannot see that one has any advantage over the other.
HINTS TO THE MANUFACTURERS OF INCUBATORS.
Incubator Case, Doors, Etc.
There are very few incubators on the market at the
present day that are built sufficiently well for the pur-
pose for which they are intended. Many incubators are
built so cheaply, and in so slovenly a manner that no
man who cares to hatch eggs should ever be tempted to
buy them, no matter at what price they are offered. They
are too expensive even if they were given away. The
first requirement for success in raising poultry is to hateh
strong and vigorous chicks, and unless an incubator is
well built, you cannot possibly do this. It is not the ma-
terial that is used in the incubator which is of so much
consequence, but the workmanship in putting it together
is of the very greatest importance. Every incubator
10
should be built of double walls throughout, and at least
on top, should have a thoroughly heavy packing of heat
insulating material. But more important than the pack-
ing is the care with which joints are made. They should
be made on proper machinery and carefully glued
together, so as to make the incubator case air-tight, es-
pecially the door should be made to fit absolutely air
tight. This is almost impossible to accomplish unless the
edges of the door and its casings are lined with felt.
There should be double doors, one glass door next to
the eggs, and outside of that a solid wood door. This
is preferable, for if chicks are kept in the dark while
hatching they will remain evenly scattered over the in-_
cubator. If there is only one glass door chicks will all
crowd to the front. This may be obviated somewhat by
placing the glass high up in the door, and leaving a con-
siderable dark space at the bottom, which keeps the light
out of the nursery. But far better than the arrange-
ment of glass doors, and egg trays is the method of con-
struction used in our Mammoth machines. These have
simply a large drawer, which fits tightly in the machine.
The egg trays are placed within this drawer, near its
top, and for airing the eggs, the whole drawer is pulled
out of the machine resting one end upon the incubator,
and the other on a stick fastened to the front of the
drawer. A small window screened with curtains is cut
in the upper part of the drawer through which the tem-
perature may be read, and chicks may be watched at the
time of hatching. This arrangement saves a very large
amount of labor, as the chicks can easily be gotten out,
and the eggs are always protected from drafts, as the
sides and bottom of the drawer are solid, and thus pre-
vent any drafts from striking the eggs.
THERMOSTAT, LAMPS, HTC.
It is immaterial what kind of thermostat is used,
whether it be composed of different metals, or ether
wafers. Everything here, as everywhere else, depends
upon the care with which they are made. Wither kind
will last a life time, if well made, but it is quite important
that ali the bearings should have knife edges and should
be patterned after the method of bearings used in weigh-
ing-scales.
When possible only one direct lever should be used,
and the method of regulating the heat should be that
which is commonly known as the damper method. Any
thermostat working on the wick of the lamp is always
more or less unreliable, as the wick sleeves are sure to
char some time or other, and thus prevent its working.
While there is a little saving of oil on the lamp trips,
they are sure to spoil the hatch sooner or later, and thus
may be expensive in the end.
Lamp bowls should be made either of galvanized iron
or copper or brass, and they should be well and strongly
1]
made, and the upper part of the lamp bow! should be per-
fectly smooth, sloping toward the edges, so that no oil
will stand on it.
If the boiler of the incubator is constructed properly,
arrangements to keep water on the lamp, or around the
flame are unnecessary, and had better not be used. The
final outlet of the bad air from the lamp should be at
least twelve vertical inches above the flame, no matter how
far endways, or sideways this outlet is found. Other-
wise there will be heating of the lamp flame, and of the
lamp bowl, and there is danger of generating explosive
gases.
Lamp chimneys should be made of iron with a large
mica window at least 2 inches in diameter, but see that
your chimneys are faultlessly made, for drafts from the
chimneys will cause the lamp-flame to smoke, and be-
come dangerous. The lamp on any incubator should be
carefully locked. No spring arrangement is ever to be
allowed, for springs, no matter how good they are, will
get weak in a short time, and the lamp will not fit prop-
erly. The lamp should be so securely locked to the in-
cubator that it cannot be knocked off; even if the incu-
bator should be overturned the lamp should still stick
to it. To encase the incubator in metal is useless, the
danger comes from the lamp, not from the incubator.
Common sense requires these precautions.
Thermostats should have a protective covering so that
cats and dogs, or children or plaster that may fall from
the wall on them, would not throw them out of position.
It is to be remembered that any thermostat must of ne-
cessity be a delicate instrument, and it should be made
accordingly, and treated accordingly.
CARE OF BREEDING STOCK AND FERTILITY
OF EGGS.
We have used eggs from birds kept under all sorts of
conditions. Birds that have run on the wide range, and
birds that for several years have been confined in very
small pens, also eggs from birds fed on pure grain and
birds that were fed on nothing but garbage. We have
not been able to detect any difference in the fertility, and
vigor of the embryo in the eggs, as far as external condi-
tions and feeding of stock is concerned. More seems to
depend upon the vigor of the fowls, and especially the
males. Males should have a rest some time during the
year, or should be interchanged with others. This much,
however, is certain, that birds kept on a very large range
have the best chance of producing vigorous strong germs
in the eggs intended for hatching, but it must remain
for further experiment whether confining birds or diff-
erent methods of feeding affect the vigor of the embryo
in the eggs.
12
CARE OF THE EGGS.
One of the first requirements for successful incubation
is the proper handling of the eggs. Eggs should be gath-
ered as soon as they are laid, and not exposed to the heat
or bright sun. They should be carefully placed in the
ordinary market egg cases, and should be kept in a cool
place (55 degrees), but under no circumstances should
they be exposed to draft of any kind. The fresher the
eggs are, the better they will hatch.
If it is expected to hatch every egg that is placed in
the incubator, no eggs over three days old should be
used. However, we have sometimes had reasonably good
results from eggs that were three and four weeks old.
There is a popular idea that eggs intended for hatching
should be turned every day. We doubt very much if this
does them any good. It is of much more importance to
handle the eggs very gently, for the jarring and shaking
of them is a heavy strain on the various membranes of
the egg. Violent shaking of the egg will destroy all its
possibility for hatching, and the less eggs intended for
hatching are handled, the better it is.
If eggs have become soiled, they should be washed, but
it would be better not to use any eggs that have been
washed, or subjected to any unnatural conditions in any
way. <A clean egg gathered from the hen’s nest and
placed immediately in the incubator has tremendous
chances over an egg that has been more or less abused.
Defective eggs, and those with round ridges through
the middle, or rough shells, or imperfectly formed shells
had better be discarded, as well as very small or very
large eggs. They will hatch very well at times, but
the chances are somewhat against them of producing a
perfect chick. Remember, do not expose your eggs to
the sun. Keep them cool, (about fifty or fifty-five de-
grees), but do not chill them, and above all handle them
very gently, and keep them out of the draft.
THE PROCESS OF INCUBATION
THE RIGHT TEMPERATURE FOR INCUBATION
We have made a large number of tests of the temper-
ature of eggs under the sitting hen. It is rather diffi-
cult to arrive at any exact temperature. The eggs on the
outer edges of the nest are usually considerably colder
than those in its centre, but as she shifts them around
a great deal, all the eggs receive the highest temper-
ature which she produces sometime or other during the
day.
If the thermometer be placed among the eggs, we have
not generally found it to register over 100 to 102 degrees.
If the thermometer be applied to the hen’s body, we
have quite often found a temperature of 104 to 107 de-
grees. Great care must be exercised in taking the hen’s
temperature, for as soon as she gets the least worried, her
temperature rises rapidly, and often in a few minutes reg-
isters 108 degrees or more. Even a non-broody hen,
with normal temperature of 98 will soon rise to 102 if
agitated.
The safest method of arriving at the temperature of in-
cubation under the hen is to thrust a sensitive ther-
mometer quickly into the middle of the egg taken from
the center of her nest. Numerous tests which we have
made in that way, always range closely between 102 and
104 degrees. Upon the whole, perhaps no better incu-
bating temperature can be found than 103 deegres.
In our practice the thermometer bulb is placed level
with the top of the eggs, and either left in contact with
the eggs, or very close to it, and the eggs are incubated
throughout the hatch from the beginning to the end
at 103 degrees. Under this temperature if the eggs are
fresh, chicks are almost always all hatched at the end
of the twentieth day. Sometimes, if weak, or old, they
will not hatch till the 21st day or later.
It is very important that the temperature be 103 de-
grees at the very beginning and should not drop below it
during the first six days. After being placed in the ma-
chine eggs should reach 103 in three to five hours
If it takes longer to reach the proper temperature, eggs
are sure to suffer. Nothing is so bad for eggs as say 80
to 85 degrees of heat for the first day. Some successful
hatchers even start at 106 and gradually drop down to
1038. Watch your machine the first week as the apple of
your eye. After that you may sleep in peace.
Beginners are often needlessly worried if the tempera-
ture accidentally for a short time drops too low. Eggs
will successfully withstand quite a considerable amount
of low temperature, if it comes only once, but they will
14
not stand endless see-saws of it. We have successfully
hatched eggs that accidentally were left out of the ma-
chine as long as from ten to twenty-four hours, and
reached a temperature as low as fifty degrees, during
part of the time. No bad effect seemed noticeable. The
chicks were perfect. But if there is a see-saw of tem-
perature, say even between 95 and 105 degrees, for sey-
eral days, the hatch is usually spoiled.
Overheating spoils the eggs much quicker than low
temperature. It depends a good deal on the age of the
embryo, how fatal overheating will prove. Up till the
6th day a temperature of 110 for several hours wili
probably kill all the germs, though we have had them
withstand this for fifteen minutes or so, but where they
were exposed to this temperature for a longer period,
we always found all embryos dead.
We have one case on record, however, where the in-
cubator, by accident, had reached 115 degrees (end of
7th day of incubation), and stood at this probably for a
full hour or more. We only lost about 10% of embryos.
These ail died within the next day. All the rest of the
embryos hatched perfectly, there were neither cripples
nor weaklings of any sort.
CRIPPLHS.
Neither overheating nor chilling the eggs will cause
-cripples. We have never found any other cause of crip-
ples than drafts in the machine or too cold a bottom in
the nursery. We had one case where the incubator
haiched reasonably well, but 65% were cripples. It was
found the bottom of the nursery registered only 75 de-
grees. For the next hatch the nursery was filled with
straw and cotton batting, and no cripples appeared.
Perhaps the under side of the egg being so much colder,
retards the growth of the embroyo on that side, or chills
it, and thus deranges the normal development of the
chick.
It has been claimed that lack of turning causes crip-
ples, but we have not found it so. In one of our tests,
one half of the incubator was not turned at all during the
entire period of incubation and the other half was turned
three times a day. The half of the incubator which was
turned hatched normally. The half that was not turned
at all, hatched but very few chicks, but there were hardly
any cripples. Most of the chicks grew to maturity, but
did not get out. Many died during the second week, but
not a single germ was stuck to the shell. In the half
that was turned, there was one germ stuck to the shell.
Evidently turning or not turning has nothing to do with
germs sticking to the shell. Such germs are defective.
They have risen to the top and in some way become at-
tached to the shell, but probably not till after they
were dead. Their death is probably the cause of adher-
ing to the shell. At any rate, such could not have been
saved by turning. Ill-fitting doors will almost certainly
cause cripples in cold weather.
15
TURNING THE EGGS.
Our present practice is turning the eggs twice daily,
twelve hours apart, as nearly as possible. We have had
very successful hatches, however, where the eggs were
turned only once a day, and we have even had really
good hatches where the eggs were turned only five times
during the entire period of incubation, but upon the whole
our experience tends to show that turning twice daily
brings decidedly the best results, providing a mechanical
turner is used. If the eggs cannot be turned in the ma-
chine without opening it, they should not be turned at all
for the first three days, and thereafter only once a day,
for only strong eggs will stand opening tne machine twice
a day, all the weaker ones will die in the shell or hatch
with protruding entrails, unabsorbed yolk, ete.
THE MECHANICAL TURNER.
The mechanical turner was used years ago, but proved
a failure. For that reason it was one of the last things
we tried. But one day after a miserable hatch, such as
might even make a strong man almost come to tears,
we sat down dejectedly in the woodshed by the old hen,
trying to make up our mind whether to abandon the
whole wretched hatching business or to try it blindly once
more, we noticed that she shifted her eggs around every
20 minutes or half hour, but she did not get off the nest
to do it. She seemed to hug her eggs all the closer while
she turned them. This was a lesson, we had not watched
nature close enough in this respect. We built a turning
rack, so that we could turn eggs as did the hen, without
exposing them to the outer air, and in our very next hatch
we suddenly found ourselves much nearer the goal. The
easiest way to make such a mechanical turner is to use
thin strips of wood %-inch thick and about %-inches
wide. Make a rack of these to fit closely into your in-
cubator tray after the manner of a ladder with the rungs
about 1% inches apart. The side of your rack parallel
with the rungs should be two inches shorter than the
tray, so that this rack can slide forward and backward
upon the tray. The eggs are placed between the rungs
and when the rack is moved forward or backward all
the eggs are turned. The rungs of course are nailed so
that when the rack is placed upon the tray, the side or
the rungs is at right angles with the bottom of the tray.
A thin strip of wood nailed on the top of the wire-bot-
tom of tray on its sides makes a nice rail for the rack
to slide upon. Small holes can easily be bored through
the door of the incubator through which one or two
small wire hooks can be inserted to pull or push the turn-
ing rack forward or backward without opening the door
of the incubator. A plug must be inserted in the holes
after turning. This turning-rack takes up some space
and not as many eggs will go into the machine, as with-
out it, but you will get more chicks out of the machine
by using it.
16
It seems that so simple a thing as this ought to have
been found out long ago, but apparently it was not. It
took us six weary years to discover this as well as other
things. The success and failure of a hatch sometimes de-
pends on very little things. There are a thousand wrong
ways to hatch eggs, we know a good many of them.
There is only one right way, we hope we have discovered
that in part at least. Remember, turn your eggs twice
a day, but never open your machine more than once a day.
Never!
TESTING EGGS.
In our practice the incubator is opened for the first
time on the 84th hour. The eggs. are taken out and
tested. The tray is set on a table with a blanket placed
under the tray to protect the eggs from cold air circling
around underneath them. They are left exposed on top
We are using a 16 candle power electric light bulb en-
closed in a tin globe (can be made out of a baking powder
can), which has two round openings one inch in diam-
eter. The eggs are held up two at a time, one against
each opening, when their contents may be clearly seen.
A darkened room must be used. When no electric light
is available, the best method is to make a tube about
fourteen inches long of black paper, roll it into funnel-
shape with the smaller opening about 1% inches in di-
ameter and the larger about six inches. Take an egg,
place it against the small end, hold up to sunlight, and
look through the large opening, the embryo may then be
clearly seen. Practice will soon teach to distinguish be-
tween the fertile and infertile egg.
Whatever method is used, care must be taken in hand-
ling the eggs very gently, and they should never be ex-
posed to strong light except for the briefest possible mo-
ment, nor should they be suddenly taken from a dark in-
cubator into the glaring sunlight.
It should be remembered that the hen generally hides
her nest, and eggs are never exposed to strong light.
While it is not known what damage might result from
exposure to strong light, it is not likely that nature has
made any provisions against it. Whatever is done with
eggs, be careful not to transgress upon nature’s methods
COOLING THE EGGS.
We have not come to any conclusion as to the length
of time eggs should be cooled. The investigation of de-
sirable hatching conditions has been so exceedingly ted-
ious, and in order to arrive at certain results only one
thing can be taken up atatime. It is undoubtedly best to
follow the natural method as closely as possible, asthehen
does not leave the eggs more than once a day for over
five to fifteen minutes, and the cooling of the eggs for a
similar length of time probably comes as near being right
as possible. Under no conditions should the eggs be
cooled more than once a day, or be removed from the ma-
chine more than once in 24 hours.
17
INFERTILE EGGS.
About the fourth day the embryo will appear in spider-
like form in the fertile egg, the red blood veins issuing
from the centre in all directions. This is the natural ap-
pearance of a vigorous germ. Where the veins have run
together into a bloody streak, the germ is dead. Experi-
ence alone will teach to distinguish between living and
dead germs during later periods of incubation. An
infertile egg shows perfectly clear before the tester, ex-
cept that in white-shelled eggs the yoke may be clearly
seen.
The object of testing eggs is to secure the infertile
eggs. If eggs were not much more than three days old
when put in the machine, these infertiles that are perfect-
ly clear are practically as good as any other egg not over
seven days old. However, they should not be sold for
fresh eggs, but they are excellent for baking, cooking,
etc., and are decidedly superior to storage eggs. In
testing the eggs for fertility, they should be taken from
the incubator without turning, the germs will then all be
found lying on the upper side of the egg. They should
be held up to the light and if turned at all, it should
be done gently.
After all the infertiles have been removed, these latter
should be re-tested to get the perfectly good eggs. Hold
the egg up to the tester, then give it a quick jerking turn,
if the egg looks watery then, it is no longer good. It needs
experience to distinguish good from bad eggs. Break
open enough till you find out.
HOW TO TELL INFERTILE EGGS.
There is absolutely no way to distinguish a fertile from
an infertile egg without incubating it for some days. All
advertisements to this effect are frauds pure and simple.
Nor can the difference be found out by breaking open the
egg. There is a white spot, the germinal vesicle, in each
and every egg laid by hen or pullet, but many an amateur
cannot discover it, and he thinks what he does not see
is not there. This germinal vesicle looks precisely the
same to the naked eye in the impregnated or unimpreg-
nated egg. Under the microscope the difference may
be seen. The germinal vesicle in the unimpregnated egg
is a simple cell, in the pregnated egg there is a ridge, or
row of cells, but several days, and staining fluids are
required to prepare an egg for microscopical examina-
tion.
VENTILATION OF EGGS IN THE INCUBATOR.
Perhaps there is no subject about which there are more
wild theories rampant than the question of ventilation.
As one reads the various incubator catalogs, he is sur-
prised at all the so-called wonderful discoveries each man-
ufacturer has made. Nevertheless, nobody ever seems
to have made any sort of an investigation that would
pass muster in a scientific laboratory.
18
There has been a constant reiteration of the great ne-
cessity of fresh air, but nothing has proved so costly to
us as the apparent reasonableness of these theories. For
many years we believed this firmly and sacrificed about
$2000 worth of eggs to it.
Many an incubator have we built to improve ventila-
tion, but the results have been exceedingry disastrous.
In not a single case have we had a fair hatch where any
large amount of air was admitted into the machine
After some years of experimenting we finally invented a
device by which to test conveniently the relative amount
of carbonic acid gas under the hen and in incubators.
We were very greatly surprised as soon as we tested con-
ditions under the hen. We found the carbonic acid gas
under her very great indeed, much greater than in any
incubator. We also discovered at once that the incu-
bators with the least ventilation, showed much more car-
bonic acid gas than those pets of ours with much ventila-
tion. And the hatches from the incubators with poor
ventilation proved very, very much the best.
We also had one machine that had been a puzzle for
a long time. It was made in a very crude manner by
somebody and was a forbidding looking affair. We
had purchased it from one of our customers unseen, or
we certainly would not have bought it. But we had
bought several hatches of remarkably fine chicks from
this machine and so we risked it with eggs. We had
a fine hatch and it was run many times and never failed
us. The machine had a capacity of about 800 eggs and
had only one 1-inch opening for ventilation, which was
screened with two layers of burlap. When the carbonic
acid gas test was applied to this machine, we found it con-
tained by far the greatest amount of any machine in the
hatchery. So far it was hardly possible to doubt that
too much ventilattion was the cause of many failures.
We shut up the ventilators on our machines and stuffed
up all cracks and quite remarkable improvements appear-
ed at once. The chicks were much stronger and larger.
We thought perhaps the air-space surrounding the
eggs was too large, as even with our best incubators
we could not equal the hen in carbonic acid gas. We
then built an absolutely air-tight machine cf galvanized
iron throughout, that had almost no extra air space and
no nursery. This would even beat the hen on carbonic
acid gas, but we were never able to reduce its moisture
much below 90 on the wet bulb, and every hatch proved
a dismal failure. But undoubtedly not on account of too
much carbonic acid gas, but on account of too much
moisture. We found the woodencase with cloth screens
necessary to produce an incubator sufficiently dry when
all ventilators are closed.
We subjoin tables of the tests on carbonic acid gas
evolved both in incubators and under the hens. These
tables are the average of a large number of hatches,
where practically every fertile egg produced a perfect
chick. They are taken from hatches of eggs during the
19
moulting season, when eggs are not naturally very vig-
orous. We early found that little is to be learned from
successful hatches from very vigorous eggs. They will
hatch anyway, and do not reveal the weak points of an
incubator. Moreover, a hen was set each time as the
incubator was set, with eggs taken from the same lot, and
only such hatches are used in this table where both
the hen and incubator brought off hatches in every re-
spect alike, even to the relative weight of eggs and chicks.
Thus the utmost precaution has been taken to secure a
standard hatching table. We believe that conditions
which produce perfect chicks from comparatively weaker
eggs, must be very nearly ideal. Such are represented in
our table, so far as temperature, moisture, carbonic acid
gas and structure of machine is concerned. The values
obtained were from machines constructed like the one
shown on page 4. The table for hens are from a
Barred Rock and a Buff Orpington, sitting in roomy nests
with straw bottom. It will be seen that the amount of
carbonic acid gas varies more or less, as also does the
moisture, and accordingly when neither runs higher or
lower than any values given, no attention is paid to either
carbonic acid gas or moisture in our hatchery. It is not
necessary to have these the same every day so long as
they come reasonably near this standard.
STANDARD HATCHING TABLE FOR INCUBATORS.
Day of _ | Teme | Cotccmn [Cute 0S || Tevet ot] Maen Eee
Incubation | ature- | meters of air | Acid Gas Bulb Humidity | were
1 103 86 49
2 103 7a ‘85 47
ape: 103 Oe Pat 85 47
my 103 Sw! eee 49 10
5 103 400 1 85 47 10
6 103 400 ‘in 83 42 10
7 103 320 ar 81 38 10
8 103 240 5 82 40 10
Sar hs 240 5 83 42 10
10 103 240 5 83 42 10
rfl 103 200 6 82 40 10
he 103 160 7 83 42 10
13 103 120 8 83 42 15
14 103 120 8 Ss > 47 35 oe
15 103 120 8 85 47 15
16 103 80 8 83 42 15
17 103 50 9 84 45 15
is 103 40 10 85 47 15
19 103 40 10 85 47 Eggs pipping
20 103 50 9 92 68 Hatch half out
21 103 40 10 84 45 Hatch all out
ee
RECORD OF TWO HENS
: 1 2 1 2
tncube- || Vol. Air | Gas | Vol. Air | Gas Wer | Mois hen of
gL (rR eS aaa ae
PAG bg hige cae Jeg 5
3 Rie
4 ee RS NSIS
By lta Pega nag
6 [8 86 | 49
7/8 al ee
8 |§ Slag (cada fb ai
10 | i Eel aaa
11 |S fda Ne a
12 |s roy EL
13 = a ORE ea ee ¢
14 |& 84 | 45 x
15 SAO REY iti,
16 ih ae
17 SOL AED A AUG ey, We eee Rema Te Seg
18 SOD le ZOU ES ie kl, Le in| PORES.
19 20. 20 20k 20 epee hh Cones Chicks Pipping
aH 20 20 724) 20 S545) oe All through hatching
22) Hee es -- | -50-_| 9
The volume of air given in these tables are the num-
ber of cubic centimeters of incubator air which it took
to cloud one cubic centimeter of lime water. (The first
distinct clouding is the point used in the _ tables.)
These are exact measurements and should be used in fut-
ure investigations, to avoid the confusion of different
standards. The figures for volume of carbonic acid gas
are an arbitrary graphic representation of its density, as
indicated on the piston rod of our air pump. They show
relative, not actual values, but most admirably serve its
purpose to show the difference between hen and incu-
bator and different days of incubation.
The actual amount of carbonic acid gas present in an
incubator, it should be remembered, is also directly de-
pendent upon the number of fertile eggs in a given en-
closed space. These tables are not to be used for the
purpose of guiding ventilation, in the sense of admitting
air into the incubator in case there should be found more
gas than our tables show. Keep your incubator closed
tightly, no matter how much carbonic gas is found in
it. We, ourselves, have not been able to obtain any
higher values, and are of the opinion if we could secure
21
a machine giving higher values, it would be still better,
for as will be seen from the tables giving the records of
hens, that the amount of carbonic acid gas is much
greater there.
It will also be seen that the amount of gas under the
hens is quite variable, depending upon how closely the
hen is setting.
We take it, that these investigations, prove, not act-
ually how much gas is necessary to hatch eggs, but that
absolutely confined air is of the very first importance in
an incubator. If you confine the air in your incubator
there will always be more or less carbonic acid gas
present.
On these measurements human breath shows clouding
at about 20 to 25 cubic centimeters, or 25 volumes of gas
on the figures for carbonic acid gas.
It is noticeable also that even the chicks two days old
under the hen’s wing, live in the presence of much car-
bonic acid gas.
Notice also that these hens bringing off perfect hatches
only left the nest five or six times altogether. In cool-
ing eggs this fact should be taken into consideration.
A Be
© SQ co ~~ & IG
R
|) rd oe a
(a —
3. P. Cook’s Carbonic Acid Gas Test. Price, $5.00.
a, graduated piston rod (for each fifty cc.) b, air
pump; c, rubber tube; d, glasstube; e, five ce graduate;
f, limewater.
Ze
METHOD FOR TESTING CARBONIC ACID GAS.
Our method consists in withdrawing a certain portion
of air within the incubator taken directly above the eggs,
and about twelve inches from the front of the machine.
A small hole is bored through the frame of the door
about one quarter inch in diameter, through which a
small rubber tube with a glass end is introduced. This
rubber tube is attached to an air pump, holding from
250 to 300 cubic centimeters of air. The piston of the
pump is graduated for each 50 cubic centimeters.
After the air is withdrawn from the incubator, it is
passed through one-half centimeter of lime water, and the
point where the clouding of the lime water begins is
noted.
As is well known, this clouding is due to the amount
of carbonic acid gas, which has passed through the lime
water. The point at the piston is then read, which in-
dicates directly how many cubic centimeters of air have
passed through the lime water to effect the clouding.
The piston rod is graduated up-side-down, beginning
with 10 and ending with one, so as to indicate directly the
amount of carbonic acid gas.
For instance, if the first fifty cubic centimeters of air
effect the clouding of the one-half cubic centimeter of
lime water, the piston rod will stand at 10, which we
designate as 10 volumes of carbonic acid gas present in
the incubator. This is, of course, wholly arbitrary, but
it serves very well to give an indication of the relative
amount of the carbonic acid gas present. What this
measurement actually amounts to is this: The fifty
cubic centimeters of incubator air contains enough car-
bonic acid gas to cloud one-half cubic centimeters of
lime water, which is equal to 100 cubic centimeters of
incubator air clouding one cubic centimeter of lime water.
We suggest that all incubator tests on carbonic acid
gas to be made in the future, be made upon this measure-
ment, as it is very convenient indeed, and serves all prac-
tical purposes in the best possible way. Some unit of
measure will have to be decided upon, and as all our
tests have been made on this, it would only confuse mat-
ters if any additional standard of measurements were in-
troduced.
The lime water which we use is prepared in the ordin-
ary way, just taking a piece of unslaked lime and dissolv-
ing as much of it in water as the water will take up per-
fectly clear, and using the clear part of the water. We
use the ordinary five cubic centimeter graduate. The
whole outfit is sold for $5.00 to anyone who is interested
in these experiments. It is necessary to clean the
graduate after each test, as more or less clouding will
be effected, which will interfere with the reading.
If an ordinary rag will not clean it, use a drop of
hydrochloric acid, which will clean the graduate in-
stantly, and it should be well rinsed after cleansing.
In all our tests the air was not withdrawn from the
incubator until it had been closed for 24 hours.
23
THE MOISTURE PROBLEM.
There is no end to the theories about moisture in an
incubator. There seems to be an almost universal opin-
ion that eggs will be helped by being sprinkled, or by
filling the incubator by some means with moisture.
Undoubtedly the moisture problem is a very important
one in artificial incubation, and it is by far the most
difficult of solution. It is comparatively easy to deter-
mine the relative amount of carbonic acid gas under a
setting hen, and it is also comparatively easy to secure
something of a corresponding amount of this gas in an
incubator by reducing the air space surrounding the eggs,
but with the moisture problem it is different. It is al-
most impossible to find out the relative amount of mois-
ture surrounding the eggs under a setting hen. The
space is so very small that it is almost impossible to make
any test. The wet bulb thermometer is practically inap-
plicable here. The amount of moisture introduced by
the wet bulb would interfere with any correct results of
a test.
About the only other method available is the use of the
spiral hygrometers, which are very unreliable at best.
We have made hundreds of tests of setting hens, using a
spiral hygrometer, placing it as carefully as possible, and
after reading it transferring it to an incubator, and intro-
ducing moisture into the compartment, or withdrawing it
until we found a corresponding reading, and then compar-
ing it with our wet bulb instrument.
There would be only one other way of measuring the
moisture under the setting hen, and that would be by
withdrawing a small portion of air, and by analysis de-
termining the actual percentage of moisture present in
it. For this we did not possess the necessary instru-
ments, and it is very doubtful if it would be of very much
value. The results which we have obtained have been
variable indeed, ranging as low as 35% of humidity, and
as high as 60%. It has been impossible to get almost
any two readings alike. Perhaps the only actual result
that is dependable is the fact that in all cases the hu-
midity of the air surrounding the eggs under the hen
was considerably drier than the outside air.
It was also found that the amount of humidity under
the hen bears no corresponding relation to the humidity
in the outside air. Some of our tests of hens setting
practically out of doors, in rainy weather, with the rain
dropping over their wings, still showed only about 40°
of humidity over the eggs. But to repeat, none of the
tests made can be regarded as in any sense absolutely
accurate, so we have no clue as far as the hen is con-
cerned, what the amount of moisture should be sur-
rounding the eggs. Perhaps the safest way is to re-
gard the lowest reading the most accurate, as nearly all
instruments register higher than actual humidity.
When it comes to the incubator it is easy enough to
determine the relative humidity inside the egg chamber.
All that is needed is a reliable wet bulb thermometer.
24
Place it carefully, and read the difference between the
dry thermometer, and the wet bulb thermometer, and the
amount of relative humidity can be readily determined
by the use of psychro-metrical tables published by the
United States weather bureau. (A number of so called
incubator hygrometers are on the market, which pretend
to give a direct reading of the humidity in the egg cham-
ber, but these cannot be used for anything like accurate
work. Some of them do not read low enough, and it is
doubtful if others are sufficiently accurate. Any hygro-
meter that does not read as low as 385° is worthless for
incubator use, and should not be sold for that purpose.)
For all practical purposes it is much simpler to disre-
gard the actual relative humidity, but carefully note the
depression of the wet bulb thermometer. In that way
all confusion and difficulty is avoided.
The only method open to determine the right amount
of moisture for successful incubation, is by repeated ex-
periments. Our experiments in this line have continued
for over six years, and hundreds of hatches have been
carefully noted. We have never found a good hatch
unless the air in the incubator was comparatively dry.
The percentage of about 40° or 45° humidity seems to
give the best results, which is equal to a depression of
about 18° to 20° on the wet bulb thermometer. Where
it is possible we prefer to use 20° of depression for
hatching, i. e., 88° on the wet bulb. We have had uni-
formly good results at this point, provided all other
things are right. There is no doubt that a great many
incubators, and a great many hatches fail because it is
impossible to get the air dry enough. Of course, on the
other hand many hatches are spoiled by the air being too
dry on account of the excessive ventilation within the
incubator chamber. But it was found in our other ex-
periments that there must be practically no ventilation of
any kind in the incubator chamber, and the air surround-
ing the eggs must remain perfectly quiet in order to main-
tain sufficient carbonic acid gas and prevent the formation
of cripples. This makes the moisture problem a most
difficult one. Incubators will act as contrary as anything
that can be imagined in this respect.
The problem in incubation is to get the air within the
egg chamber to run about 83°, wet bulb, without ventila-
tion of any sort. Where this cannot be accomplished the
hatch will be more or less a failure. Some incubators
we have had we simply could not use at all. Others of
identically the same make worked without any trouble.
Only a very few that we found needed artificial moisture,
when the machine had been made practically air tight.
One of our large machines was a constant puzzle to us.
It contained eight compartments holding 2000 eggs.
The compartments are all built identically alike. They
are all heated in the same manner by one hot water sys-
tem. They all show the same temperature yet one com-
partment runs 20% higher in moisture than all the others,
and consequently we cannot use that compartment. We
25
have been unable to determine any reason whatever for
this difference. There are certain seasons of the year,
however, when all the compartments run alike, and we
can use the whole machine. This is simply one of the
instances of the many queer actions with which incu-
bators confront us.
We find that a space about twelve inches high from the
bottom of the machine to the top is necessary to give suffi-
cient dryness of the air, which has to take up of course
the evaporation of the moisture from the egg, and still not
become too highly saturated with moisture.
We have sometimes found it quite an improvement to
slip a diaphragm, made of thin muslin, between the eggs,
and the hot water pipes, thus making two compartments
in the machine. The diaphragm should be close to the
pipes. Small openings may then be made through the
top of the machine into this upper compartment, say one
or more half inch holes for every 250 eggs. This has
a tendency to cause a very, very slow movement of the
air, and as more heat is needed to heat up the incubator
through this diaphragm, there is more dry air in the ma-
chine than can otherwise be secured. It seems the small
opening helps to dry out the air without appreciably af-
fecting the air below the diaphragm.
In smaller machines we have found a rather effective
way in allowing hot air to circulate around the heater, and
allowing it to open into the upper compartment of the
machine. This makes the circulation of the air much
slower since it has no outlet, but it seems to secure the
dry atmosphere, which is so very essential in the egg
chamber.
The moisture in the air of the incubator room has no
effect on the eggs in the machine. An incubator with
ventilators open will usually register much drier on blus-
tering rainy days than on hot, dry, or sultry days. In
warm weather the incubator ventilators do not work at
any rate, for if there is not much difference in the tem-
perature outside the machine, no air will pass through.
It may be given as a safe rule never to put water in an
incubator, on hot sultry days. If ever any moisture is
needed, it is in winter, or on windy days. Those are
the times when the incubator is actually too dry. This
will sound strange, to the inexperienced, but place a re-
liable hygrometer in the incubator on hot, dry days, and
you will find a very high humidity. The opposite will
be found on cold days, even if they are rainy. More
air is sucked through the incubator on cold, windy and
blustering days, which causes it to be excessively dry.
Sprinkling the floor of the incubator room has not the
slightest effect on the moisture within the machine. The
effect of too much moisture in the incubator will be that
many chicks are dead in the shell, as many as one half
or more sometimes.
A rough distinction may be made in this way: If the
chicks that hatch are scrawny little things with protrud-
ing entrails, or unabsorbed yolk, there was too much ven-
26
tilation. If the chicks that hatch are fairly good and
large in size, the chicks dying in the shells is due to too
much moisture. Both faults cause chicks to die in the
shell, and both must be avoided. However, it is safe
to say ten times as many chicks die in the shells from
too high humidity, i. e., too much moisture, than for lack
of it.
If moisture is actually needed, the best way to intro-
duce it is a wet sponge placed on the eggs. Water pans
may be placed in the bottom, but this does not usually
have much effect.
A Dry Ther moOmelév
B. Wet- Bulb Poychrometer
C Water-Cistern ;
1 P. Cook’s continuous reading
Hygrometer.Price, $3.00.
Zee Cooks
simplified
Hygrometer.
Price, $1.00.
DIRECTIONS FOR USING P. COOK’S HYGROMETER.
Our hygrometer consists of two accurate thermometers,
one of which has a muslin wick connected with a water
cistern, attached to it. The whole instrument is placed
in the machine like an ordinary thermometer. The evap-
oration of water from the wick around the bulb of one
thermometer causes this bulb to cool in proportion to the
amount of evaporation. The drier the air in the incu-
bator, the more rapidly will it evaporate water from
the wick and thus cause the wet bulb to read lower than
the dry bulb thermometer. Indirectly, the difference be-
tween the two thermometers indicates the dryness of the
air. This is the method used in the U. S. Weather Bu-
reau, and it has published elaborate tables from which
say
the relative per cent of humidity can be learned if once
the depression of the wet bulb thermometer is known.
We print here a part of these tables as far as they are
of use for incubator purposes. For instance, if the dry
bulb stands at 103 and the wet bulb at 83, there is twenty
degrees difference, i. e., there is twenty degrees depres-
sion on the wet bulb. The wet bulb thermometer is
technically called a psychrometer. From the table it
will be seen that there is 42 per cent relative humidity
in this case. Orif the dry bulb registers 100 degrees and
the Psychrometer 82 degrees, there is 18 degrees depres-
sion, and it is found from the table that in this case there
is 46 per cent humidity.
PSYCHROMETER TABLES.
Degrees of Depression of Psychrometer
16 | 17 18 19 | 20 | 21 22 |
98 50 | 48 | 45 | 43 | 40 | 38
100 39
102 52 | 49 | 47 | 45 | 42 | 40 | 38
Aupraney
aAnojay
52 | 49 | 47 | 45 | 42 | 40 | 38
a4 50 | 48 46 | 43 | 41 | 39
53151149] 461 44| 42 | 40
For practical purposes it is much easier, however, to
disregard these moisture percentages. It is enough to
know that when your thermometer reads 103 degrees and
the Psychrometer 83 to 85, your machine is working
properly and no further attention need be paid to it.
Ordinarily, if an incubator is once started right, and
our other instructions for closing the ventilators, etc.,
have been followed, there will be no need to use a hygro-
meter, as the moisture does not generally vary much dur-
ing a hatch. Nevertheless, it will soon pay to be in
possession of a hygrometer, but as our larger instrument
costs three dollars, it is too costly for the man who has
only a small machine. We have, therefore, designed a
much cheaper instrument, which is just as reliable, but
takes a little more trouble to use it. This is simply an
accurate Thermometer reading down to 75 degrees. A
thin piece of muslin is tied around the bulb, this is
dipped in luke-warm water and then inserted into the
incubator, through a hole bored in the door. It is left
there for ten minutes and then partly pulled out to see
how low it reads. Its lowest reading, just before the
muslin is completely dried out is its correct reading. A
number of readings should be taken, the lowest one is the
most correct. The incubator should not be opened be-
28
fore inserting the Psychrometer. Remember the differ-
ence between it and your thermometer indicates the mois-
ture. If your incubator stands at only 100 degrees, then
80 degrees on the Psychrometer indicates proper hatch-
ing humidity. It is twenty degrees difference that is
required. Use your table unless your incubator stands
at 103 degrees. The simplified instrument is sold for
$1.00, and will be found a most excellent help. Only one
instrument is needed no matter how many incubators
are used, as moisture does not need to be taken oftener
than in the beginning and two or three times during the
hatch.
We are aware that these directions require much drier
air thany many manufacturers advise, but we have in-
quired among many hatchers and we have not heard of
one of them that has succeeded in securing good hatches
at any other percentages the great claims of some
hygrometer makers notwithstanding. It should be remem-
bered however, that our figures are for incubators with
perfectly still air, i. e., without any ventilation. Still
air is not nearly as drying as air in motion.
From our standard hatching table it will be seen that
during the exclusion of the chicks we allow 92 on the
Psychrometer. This is normal and need not be changed
unless chicks are breathing heavily or standing with their
mouths open, This indicates too much moisture, as often
as too much heat. Ventilators must then be opened, or
if the machine has no ventilators, open the doors for a
minute and let the moisture escape. As soon as the
hatch is over, see that enough air is admitted into the
machine to dry out and fluff up the chicks properly.
Sprinkling the eggs will never do them any good; its
only effect is to chill them, and if they hatch at all, they
hatch in spite of it. In fact nothing that is done to the
eggs for a few minutes during the last week, helps them
in any way. We seldom ever find any need of moisture
during hatching time, only if something is seriously
wrong with the incubator moisture will help to over-
come its defects. Shut your machine tight until pipping
time, and do not open it till chicks begin to show signs
of the need of more air.
Some Typical Tests of Moisture Under Setting Hen.
7 a. m. Outside air near hen’s nest temperature 52
degrees, moisture full saturation or 100 per cent, moisture
under the hen, 49 per cent. 12, noon, temperature out-
side, 74 degrees; moisture 58 per cent; moisture under
the hen, 40 percent. 5 p.m. Temperature 66, moisture
61 per cent. Moisture under the hen 40 per cent. In all
the numerous tests we have made, we always found much
less moisture under the hen than in the air around her.
As she heats the air in her nest, it would naturally reg-
ister drier than the outside air, unless she supplied mois-
ture from her body, but as all tests show this is not the
he)
case. The hen does not sweat through her skin and it
seems that her feathers asbsorb the evaporation from
the eggs. We had one White Rock hen sitting on damp
ground and the moisture under her always ran between
60 to 65 per cent, but all the germs rotted in the shell,
only three lived till the 21st day, but did not hatch. The
other tests above given are from hens that brought off
normal hatches.
Where we made daily tests for moisture, the hens al-
ways brought off poor hatches, due no doubt to disturb-
ing the hens too much.
HELPING CHICKS OUT OF THE SHELL.
There is little use to help chicks out of the shell when
they have not been properly incubated, but in the moult-
ing season we have sometimes found that the stragglers
can be helped to advantage. A chick should never be
helped too early, and unless it is plump and in every re-
spect perfect when helped out, it is not worth anything
In the time that eggs are naturally fertile, all chicks will
usually pop out without any help. Chicks too weak to
get out then is a sure indication of faulty incubation. No
chicks should be helped out until the hatch is nearly
over.
TYPICAL WEIGHTS OF A GOOD HATCH.
100 Fresh eggs, 11% lbs.
100 clear eggs 10 ibs., 6 oz. (15 days in incubator),
at 85 Psychrometer reading.)
100 chicks 8 lbs., 1 oz.
GOOD HATCHES ATTRIBUTED TO WRONG CAUSES.
Here it is well to point out that frequently good hatches
are attributed to wrong causes. Mr. ‘‘A’’ puts a pan of
water under his eggs, the last few days, or sprinkles
them or gives more ventilation, etc., and has a good
hatch. He concludes this is the thing to do. But it may
have had nothing whatever to do with the good hatch.
The fact is that strong eggs hatch well in spite of a
good many things. We dropped a tray of eggs once.
Two-thirds of the eggs cracked. (16th day of incuba-
tion.) We patched them up with celloidin and they
all produced remarkably strong chicks. Nevertheless,
cracking eggs is not the best way to hatch them. It
should be remembered, the critical period of incubation
are the first six days, and it may almost be said, that
it does not matter what happens after that. Certainly
eggs will stand quite a lot of abuse after that and still
hatch well. So far as ventilation is concerned, it may
be said that most arrangements do not work, which is
their recommendation. If the ventilators of the incu-
bator actually get to work, then they produce mischief.
If the incubator is placed in a room where the air is
still, there is but very little ventilation going on inside
the machine, but if the air of the room gets in motion,
30
it will be sucked through the ventilators of the incubator,
and a spoiled hatch will follow. Too much ventilation
produces small, scrawny chicks with protruding bowels,
etc. A spoiled hatch from too much ventilation is about
the sickliest sight imaginable. The glowing claims of
incubator manufacturers that their machines change the
air ever so often, are fortunately not often true, but
when they are true their machines fail to hatch.
It is not known whether the amount of carbonic acid
gas has anything to do directly with hatching, for it
varies greatly under different hens. It may be that all
that is required is absolutely still air in the incubator.
In still air the gases do not diffuse very readily. We
found in one machine that had eggs only on one tray,
twice as much carbonic acid gas as on the other tray
without eggs. As a rule, there is a little more at the
bottom than near the top of the machine, which is
natural, since the carbonic acid gas is heavier than air.
The fact remains, however, that eggs under the hen are
incubated under the pressure of a very large amount of
carbonic acid gas. This was found true even of a tiny
bantam hen that weighed only about one pound, but the
percentage of carbonic acid gas under her was as great
as under the large hens. This proves conclusively, that
there is no so-called ventilation under the hen, nor any
diffusion of the natural gases, or the carbonic acid gas
would have been carried away.
The chief value of these measurements, as we regard
it, is in the fact that they pointed out the right way to
build an incubator, i. e., one that surrounds the eggs with
still air, and thus produces conditions similar to those
under the hen. There is, of course, no reason to believe
that carbonic acid gas itself helps the hatching. Itis a
waste product of the respiration of the embryo but em-
bryonic respiration is a decidedly different process from
respiration of the full grown hen, and a large amount
of carbonic acid gas may not be detrimental, or it may
have a sort of symbiotic action, but such consideration
we may leave to the professional biologist.
Ordinarily the user of the incubator need not test the
carbonic acid gas. Let him follow our directions in con-
structing his machine, and he will not generally experi-
ence trouble. However, the carbonic acid test is the only
reliable guide to the ventilation.
METHOD OF HATCHING IN P. COOK’S MAMMOTH
HATCHERY.
(The method here given has reference to incubators
sold commonly to the public, as this will be of great use
to persons who already possess incubators. The prin-
ciple is exactly the same as that followed in Mr. Cook’s
own mammoth machines.)
The first thing that is done is to see that the incubator
is in good working order, the lamp burning properly and
lamp fountain not leaking and thermostat in perfect
31
order. Then the door is examined, and if it does not
fit air-tight, strips of felt are nailed around the edges,
so as to make it fit tight. One or two layers of burlap
or cotton batting are placed in the bottom of the ma-
chine to make it warm enough below the eggs.
The temperature at the bottom of the incubator should
never be allowed to fall much below 90 degrees. If it
is colder than that cripples are sure to result. If the
machine has nursery drawers, it is best to fill these up
with straw or cotton for the first two weeks at least. If
the machine has no nursery the temperature at the bot-
tom of the egg-tray should be at least 100 degrees.
When the machine is heated up, the thermometer is
placed in position where the top of the eggs would come
and the regulator adjusted to hold the machine at 103
degrees. The machine is kept going for a day or so with
ventilators open in order to dry it out. Then a hygro-
meter is also placed into it and watched till it sinks to
83 degrees. It may take several days to dry out the ma-
chine sufficiently. Then the ventilators are all closed
and the hygrometer read again. If it stands between 80
and 83 degrees, it is all right. If it stands above that,
the machine must be further dried out. There is not
much probability of a good hatch if the hygrometer at
the beginning of a hatch remains as high as 87 for more
than a day.
We had to run one machine for three weeks, before it
became dry enough for hatching. If you cannot make
your machine dry enough do not waste your eggs on it.
We have never come across a machine too dry, if all its
ventilators are closed.
Next the egg trays are taken and fitted with a me-
chanical turning rack as described elsewhere. The eggs
are placed on the tray with the turning rack in position.
They are laid flat on the side and not crowded. You can
get more eggs into the machine by standing them on
edge, or even by doubling them up, and the strong
eggs will hatch that way, but the weaker ones will die
in the shell. But remember, what is not good for the
weaker eggs, is no benefit to the stronger ones either. Do
not begin the poultry business by abusing your chicks
before they are born. It is knocking your profits with a
club on the head.
When the eggs are on the tray, thermometer and hygro-
meter are then placed in position and all outgoing venti-
lators are shut tightly. The best way to do this is to
stuff a tuft of cotton into the holes. It need not be
stuffed very tightly. Those machines that have the air
intake over the lamp or around the heater, need only
to have the outlets closed, for as soon as these are closed
no more air passes through them into the machine. On
other machines all ventilators must be closea.
The eggs are turned by the mechanical turner after
six hours and after that every twelve hours apart, but
under no conditions must the machine be opened for the
first 72 to 84 hours.
32
On the morning of the fourth day the incubator is
opened for the first time and the eggs are taken out
and aired for about ten minutes. They are also tested
for infertiles at this same time. Then the eggs are re-
turned to the incubator and turned mechanically twelve
hours after this without opening the machine. At the
next twelve hours the eggs are aired again for ten minutes
and so on till the twelfth day. After that they are aired
15 minutes, but never under any circumstances is the
machine opened more than once a day. This method,
ventilators closed, eggs aired only once a day, but turned
twice daily, and 88 degrees on the psychrometer, we
have found an unfailing cure for chicks dying in the
shell. But no one of these details must be omitted, or
the hatch may be spoiled.
On the 18th day the machine is closed, but small ven-
tilators may be left open, if your incubator room is free
from drafts. There will be no trouble, if these directions
have been followed, with chicks getting out of the shell.
There will be a downy lot of fine fluffy balls, as lively as
can be wished in your machine next morning.
In one respect nothing is so important as this closing
of the ventilators, especially if your incubator stands
in a room that has the least draft in it. Eggs will not
hatch to the best advantage except in absolutely still air.
For that reason taking eggs out of an incubator twice
a day is detrimental. Only the strong eggs will stand
it, the weaker ones will die in the shell. Do not worry
‘ about the need of fresh air. There is tar more oxygen
in the incubator than the eggs will ever need, as is shown
conclusively by the carbonic acid gas test. It is true the
carbonic acid gas may be a very variable quantity, de-
pending upon the number of eggs in the incubator, ete.,
but the still air is the thing of highest importance. We
know of hundreds of incubators that miserably failed to
hatch with the manufacturer’s fresh air directions which
became first-class hatchers by simply nailing up the ven-
tilators and using a mechanical turning tray.
During the proper season of the year we find that gen-
erally every germ alive at the 17th day hatches a perfect
chick. Even in the molting period we have had many
perfect hatches by this method, but occasionally some
chicks die in the shell then, however, we seldom find over
ten per cent of dead chicks even at that time. Of course
no account is taken of germs that die before the seven-
teenth day. Sometimes there are many of these, but the
fault lies with the eggs in such cases and neither hen nor
incubator could hatch them.
HATCHABLE EGGS.
There is a large difference of opinion as to which is
to be considered a fertile egg. Breeders in selling eggs
usually follow the practice of guaranteeing a certain
percentage of fertile eggs, meaning that they will replace
any perfectly clear eggs below their guarantee. There
are, however, always a certain number of eggs with im-
215)
perfect germs or weak germs, or whatever they may be
called. None of these imperfect germs can be expected
to hatch. Neither hen nor incubator could do anything
with them. Some of these germs do not develop any
farther than simply to make a bloody streak through
the yolk of the egg. Others grow longer. Some live as
long as the 13th and 14th day. In all these cases the
germ of the egg has been faulty, and it is impossible to
hatch such eggs. The proportion of these eggs depends
upon the vigor of the fowls, and to some extent also on
the season of the year. It is a good plan to test all the
eggs in an incubator on the 17th day. All of the em-
bryos dead at that time should be removed. If all the
chicks alive in the shell on the 17th day hatch, the hatch
may be called a perfect hatch, as that is all that can pos-
sibly be expected to hatch. But the great great difficulty
with incubators has been that the chicks die in the shell
after the 17th day. If any large proportion of chicks die
in the shell after the 17th day we consider it the fault
of the incubators, not of the eggs. After chicks have been
developed up to that stage they would probably hatch
if they had been incubated right. Our experience has
been that if everything has been right during
the period of incubation practically all the chicks alive
at the end of the 17th day will hatch.
MAMMOTH AND COMPARTMEN'T MACHINES.
We have spent a great deal of money in the attempt
to build a large compartment machine heated by only
one heater and capable of continuous hatening. Such
a machine is evidently very desirable for a large hatch-
ing plant, but we have met with only moderate success
in this direction. It is easy enough to construct a ma-
chine with any number of compartments to hatch prop-
erly if the entire machine is filled with eggs at the same
time. Then all the compartments require the same
amount of heat and the entire machine can easily be
regulated by one thermostat. But difficulty arises when
eggs of different periods of incubation are placed in dif-
ferent compartments. The eggs much ahead generate
a good deal of their own heat and have to be in cooler
compartments. It is very difficult to remove surplus heat
from such compartments without interfering with the
necessary moisture and carbonic acid gas conditions. The
easiest way to remove heat from a compartment would
be by letting it escape through ventilators, but this is
not permissable, for ventilation spoils the hatch. Stop
cocks or other methods must be used, which involve a
great deal of expense. It can no doubt be done, but we
have abandoned it for our own use. We have found
it much the cheaper method to build different incu-
bators. One machine can be used for the first week, an-
other for the second and a special machine can be built
for the last week with conveniences to take care of
the chicks for hatching.
34
j
|
|
Our machines are 22 feet long and four feet wide and
in this size we have found no need for more than one
thermostat for each machine. Each machine is built
with eight compartments independent of each other.
NURSERIES.
We have used machines with nurseries in nearly all
our experiments. We do not know of how much real ad-
vantage they are. In a big hatch chicks seem to have a lit-
tle more elbow room as they are away from the shells.
Many machines are made with drawers, but these are
not always an advantage. If a machine is made with
drawers, it should be so made that the egg tray is placed
on the drawer and always comes out with it. If the
drawers are made to slide in under the tray, there is
always trouble. As soon as the drawer is pulled out
a number of chicks will jump over the back of the drawer
and others raise their head and you can neither shut nor
open the machine or get the chicks. We prefer no draw-
ers at all unless the egg tray comes out with the drawer.
DISINFECTING INCUBATOR.
At least every third hatch an incubator should be
thoroughly disinfected. The trays and bottom should be
thoroughly cleansed. They can be washed with almost any
good disinfecting fluid or sulphur may be burned in it.
This last is the most effective method, but it will require
some days of airing before you can get the sulphur out
again. However, it is not necessary to get all the sulphur
smell out. We have had good hatches with the sulphur
smelling strongly all during the incubation.
The incubator is a splendid hatcher of all kinds of
germs and white diarrhea may be caught in the incubator.
On the other hand, the incubator should not be blamed
for chicks dying after they are some days old. If the
chicks are big and strong when hatched, you may be as-
sured that the incubator has done its part. After that
the fault lies with the brooding.
INCUBATOR HOUSES AND CELLARS.
Incubator may be placed in any room that will shel-
ter it, but a basement or cellar that is light and cheery,
and not too damp is very desirable, for the temperature
of such a place is not subject to as much variation as an
ordinary room. The most desirable temperature for an
incubator room is between sixty and seventy degrees. The
most important item, however, is, that it be well venti-
lated, but absolutely free from draft. Nothing works
so much mischief in an incubator room as drafts. In a
perfectly quiet room it is not always necessary to resort
to the mechanical turning tray. Eggs will fairly well
35
FES 14
1914
stand opening the machine twice a day for turning, only
for the one turning the eggs must be returned as soon as
possible to the machine. But even in the best incubator
room a strict adherence to our method will be found to
pay well.
A cellar three feet deep with cement floor and walls
and the rest of the building above ground, is the ideal for
an incubator house. It should be kept dry. Never
sprinkle the floor.
It is immaterial whether lamps, gas or coal, ete., is
used for heating incubators, but the fumes should be
carried off through chimneys.
CHICKS DYING IN BROODER.
It is not always easy to raise a big flock of chicks artifi-
cially, and while it does not belong here, we may as well
point out one great means of saving chicks. People have
become so accustomed to the necessity of disinfection
that they believe if they could only kill all the germs,
their chicks would do well, but they forget that there
are as many if not more, beneficial germs as there are
disease germs. Disinfection kills both the good and bad
germs. The real remedy is not always more disinfec-
tion, but better natural conditions for the chick. Prof.
Metchnikoff, head of the Pasteur Institute in Paris
hatched and tried to rear chicks under absolutely germ-
proof conditions, but found that his chicks would dwindle
away and die in a few weeks. Afterwards he allowed
his chicks to come into contact freely with the ordi-
nary dunghill bacteria and they were thriving as they
should. The intestinal canal is inhabited by a number
of bacteria that aid materially in digestion, and the en-
tire absence of these causes many chicks to die appar-
ently without any cause.
One of our neighbors, a famous breeder of Barred
Rocks, has for years claimed that the only sure way to
prevent white diarrhea in chicks is to feed them a liberal
supply of maggots. He has been a steady customer for
the rotten eggs from our hatchery. He exposes them
to the flies for a day and then lightly buries them. Shortly
there is as big a lot of wrigglers as any old hen would
want. He feeds these maggots regularly, and certainly
raises magnificent birds on them. It is probably safest
to use maggots thus produced under ground, for if the
eggs were not buried, there might be ptomaines de-
veloped.
In everything the poultryman should remember that
he cannot far transgress nature with immunity. If
chicks are once well hatched, then look to your brooding
system.
36 é
Le My ‘ll
Successful
Incubation
By P. COOK
PtiStae gt” oo ee Cee |
S pas hue’ 2 aie é
Ain Pi hw Oy er kasi
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