United Poultry Concerns <http://www.UPC-online.org>
11 April 2020

*By Karen Davis, PhD, President of United Poultry Concerns*

INSIDE THE EGG

If the egg has been fertilized, a tiny being is growing inside, whether
nestled
beneath the mother hen or crammed in an incubator among thousands of other
embryos. During the first 24 hours after the egg is laid, the tiny heart
starts
beating and blood vessels begin to form, joining the embryo and the yoke sac
that will nourish the embryo as it grows.

The nervous system originates during the 21st hour of incubation, followed
by
origination of the head and eyes. Other body parts begin to develop during
this
time, including the alimentary tract and the spinal column. On the third
day,
the embryo begins to rotate to lie on its left side. By the fourth day, all
body
organs are present, with the nose, legs, wings, and tongue taking shape and
the
vascular system in place.

On the fifth day, the reproductive organs differentiate and the face begins
to
assume a lifelike appearance. On the sixth day, the beak and the egg tooth
(a
kind of rough edge that disappears after hatching, which protects the beak
and
also helps crack the shell) can be seen, along with some voluntary
movements of
the embryo.

During the next seven days, the body develops rapidly, including the
formation
of the abdomen and intestines. Feather germs, the origin of feather tracts,
appear, the beak begins to harden, toes and leg scales start to show, the
skeleton begins to calcify, and chick down appears.

On the fourteenth day, the embryo, now covered with down, rotates to arrange
itself parallel to the long axis of the egg, normally with its head toward
the
large end of the egg near the air cell. On the seventeenth day, the chick
turns
its head, placing its beak under its right wing toward the lower part of the
enlarged air cell to prepare for hatching and breathing outside the shell.

HATCHING

On the nineteenth day, the yoke sac begins to enter the chick’s body
through the
umbilicus, and the chick positions itself for pipping the shell, that is,
for
making a hole in the shell to breathe through while struggling to get out.
On
the twentieth day, the yolk sac completes it absorption into the body
cavity and
the umbilicus begins to close. By now, the chick occupies the entire area
within
the shell except the air cell, which it now begins to penetrate with its
beak,
inhaling outside air through its lungs for the first time.

After pipping the shell to reach the air cell, the chick rests for several
hours. It then cuts a circular line counterclockwise around the shell by
striking the shell with its egg tooth near the large end of the egg, aided
by a
special pipping muscle in its neck which helps it to force its beak through
the
membranes lining the shell.

With the egg tooth, the chick saws its way out of the shell, aided by the
mother
hen if she is there and help is needed. Between 10 and 20 hours after the
shell
is first broken, the chick emerges, wet and exhausted, to face the life
ahead.

Nearly two days may pass between the hatching of the first chick and the
appearance of the last member of the brood. Thus, some chicks may be almost
two
days old by the time all of their sisters and brothers have struggled from
their
shells, as many as 16 others. However, hatching is not a haphazard process.

About 24 hours before the chick is ready to hatch, it starts peeping in its
shell to notify its mother and siblings that it is ready to emerge. A
communication network is established among the chicks, and between the
chicks
and their mother, who must stay composed while all the peeping, sawing, and
egg-breaking goes on underneath her. Since some eggs may be infertile or
aborted, the peeps tell the hen how long she needs to continue sitting on
the
nest.

MOTHER HEN AND HER CHICKS

As soon as all the eggs are hatched, the hungry mother and her brood go
forth
eagerly to eat, drink, scratch the soil, and explore. Baby chicks are
precocial,
meaning they are genetically equipped to find food and follow their own
kind, or
whoever is in charge, in the process known as imprinting. By imprinting,
chicks
learn the features of their mother hen and siblings, to insure their
survival.
They practice hygiene by preening their feathers and dustbathing almost
immediately.

The chicks venture fairly far away from their mother, communicating back and
forth all the while with clucks and peeps. The hen keeps track of her little
ones on the basis of color, possibly also by smell, and by counting the
peeps of
each chick and noting the emotional tones of their voices. Periodically she
squats down, and the chicks dash under her outspread feathers where they
stay
until they are thoroughly warmed before dashing out again.

Should a peep be missing or sound frightened, she runs to find the chick and
deliver it – not always successfully – from the hole in the ground, tangled
foliage, or threatening predator.

During the first four to eight weeks or so, the chicks stay close to their
mother, gathering beneath her wings every night at dusk. Eventually, she
flies
up to her perch, indicating her sense that they, and she, are ready for
independence.

Young chicks without their mother huddle together at night for the first
month
or two. Then one evening, you see them practicing sitting in a row, before
huddling. Then comes an evening when they are lined up on their perch,
arranging
and rearranging themselves as before, only this time they stay lined up all
night, henceforth roosting like the adults.

KAREN DAVIS, PhD is the President and Founder of United Poultry Concerns, a
nonprofit organization that promotes the compassionate and respectful
treatment
of domestic fowl including a sanctuary for chickens in Virginia. Inducted
into
the National Animal Rights Hall of Fame for Outstanding Contributions to
Animal
Liberation, Karen is the author of numerous books, essays, articles and
campaigns. Her latest book is *For the Birds: From Exploitation to
Liberation:*
*Essays on Chickens, Turkeys, and Other Domesticated Fowl* (Lantern Books,
2019).

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—
United Poultry Concerns is a nonprofit organization that promotes
the compassionate and respectful treatment of domestic fowl.
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