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Chicken Power Point #1

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Which Came First…The
Chicken or the Egg???
Created by Susan Pool
Nebo Elementary School
History of the Chicken
• There are over 350
different kinds of
• Chickens have been
known to be tame as
early as 2000 BC
• Four types of chicken
were found in the
Do All Eggs Hatch Into Chicks?
• You may wonder why
eggs in the grocery
store don’t grow into
chickens. If you tried
to grow these eggs
into chicks it would
not happen. You have
to have a rooster
present for an egg to
grow into a chick.
The Egg
• Looking at the egg from
the outside we see the
shell, which is a hard,
protective covering made
of calcium carbonate. The
shell has more than 7,000
tiny pores to let gases into
and out of the shell.
Carbon dioxide and
moisture are given off
through the pores and are
replaced by atmospheric
gases, including oxygen.
• Immediately beneath the
shell are two membranes,
the outer and inner shell
membranes. These
membranes protect the
contents of the egg from
bacteria and prevent
moisture from leaving the
egg too quickly..
• The body temperature of a
hen is approximately 106В°
F, Eggs are very warm at
the time they are laid. The
temperature of the air is
usually much lower than
106В° F, and the egg cools
to the temperature of its
surroundings. As cooling
takes place, the contents
of the egg contract more
than does the shell of the
egg. This creates a
vacuum and air is drawn
through the pores of the
• As a result, an air cell
forms at the large end of
the egg. While the embryo
is growing, the shell
membranes surround and
contain the white or
albumen of the egg. The
albumen provides the
liquid where the embryo
develops, and it also
contains a large amount of
the protein necessary for
proper development.
Parts of the Egg
• In a fresh egg, we can see
white cords attached to the
yolk sac. These two cords,
called chalazae, are made
of twisted strands of
mucin fibers that are a
special form of protein.
The chalazae hold the yolk
in the center of the egg.
The Germinal Disc
• The yolk is the source
of food for the embryo
and contains all the fat
in the egg. The small
white spot on the yolk
is the germinal disc.
This is where the
female's genetic
material is found.
How the Hen Hatches an Egg
• In nature, the female bird
selects the nest site and
lays a clutch of eggs
(usually 8 to 13 eggs), one
egg per day. Once she has
a clutch of eggs, she
begins sitting on the eggs
full time, leaving only for
food and water.
• The hen's body
temperature is 105В° F to
106В° F. When the hen sits
on the eggs, she heats the
eggs to 100В° F to 101В° F.
The hen turns the eggs on
a regular basis by using
her beak to scoop under
the egg and roll it toward
her. The humidity comes
from the environment, the
hen's body, and any
moisture she transfers
back to the nest on her
feathers. Brooding hens
often leave their nests to
feed at dawn or dusk when
the dew is on the grass.
Eggs That Won’t Hatch
• A cracked egg will not
hatch. The crack will
let bacteria in and will
let moisture out.
A Shell That’s Too Thin
• The shell of a bodycheck egg is too thin
and porous.
• It probably won’t
Double Yolked Egg
• An egg with two yolks
with most likely not
• Fertile eggs must be cared
for before they are
incubated. The eggs
should be collected within
4 hours from when they
were laid. The eggs are
not washed unless
absolutely necessary.
Water warmer than the
egg is used,so the egg
sweats and releases the
dirt. If you use cold water,
the egg will contract and
pull the dirt and bacteria
deeper into its pores.
Important Factors
• Four factors are of
major importance in
incubating eggs
temperature, humidity,
ventilation, and
• Incubator temperature
should be maintained
between 99В° F and
101В° F.
• Too much moisture in the
incubator prevents normal
evaporation and results in
a decreased hatch, but
excessive moisture is
seldom a problem in small
incubators. Too little
moisture may cause the
chick to stick to the shell
and be crippled at
hatching time.
• The best hatching results
are obtained with normal
air, which usually contains
21 percent oxygen. It is
difficult to provide too
much oxygen, but a
deficiency is possible. It is
possible to suffocate the
eggs and chicks in an airtight container.
Development of the Chick
Nine Day Old Embryo
• 1. The clear fluid
surrounding the chick is
the amnion.
• 2. The yellow area
covered with a blood
system is the yolk sac.
• 3. The dense blood
system in the piece of egg
shell is the allantois.
• 4. The milky, clear
material to the right of
the shell is remaining
white or albumen.
What’s Happening to the Chick?????
Major events:
•18 hours: The alimentary tract appears.
•19 hours: The brain crease begins to form.
•20 hours: Somites appear.
•21 hours: The brain and nervous system begin to form.
•22 hours: The head fold begins to form.
•23 hours: Blood islands appear.
•24 hours: The eyes begin to form.
After one day in the incubator
6th Day
Major Events:
•The beak becomes visible.
•The wing bends at the elbow.
•The allantois begins to fuse with the chorion.
•The ribs begin to appear.
•The gizzard begins to form.
•The intestines begin to loop.
Let’s look at what happens
to a chick while it’s still in
the egg.
Development of the Chick
• Several changes take place
during the 18th and 21st
days. The abdominal wall
surrounds the residual
yolk sac on the 19th and
20th days of incubation.
The chick draws what
remains of the yolk into its
body and "takes its lunch
with it" when it hatches.
The chick really doesn't
need to be fed for the first
day or two after it hatches.
The Hatching Process
• The hatching process can
last for 4 to 12 hours
before the chick
completely emerges from
the shell. As the chick's
head rotates from under
the wing, the egg tooth
pips the shell and
continues to break the
shell in a nearly perfect
circle from the inside until
it is able to push the top
off the egg.
• Fluid decreases in the
amnion. The chick's head
is under its right wing
with the tip of the beak
pointed at the air shell.
The neck muscle contracts
and forces the egg tooth
through the air cell, and
the chick takes it first
breath. This is referred to
as internal pipping. At this
time, you may hear the
chick peeping inside the
The Chick Hatches!!
• On the 21st day, the
chick finishes its
escape from the shell.
The egg tooth makes
the initial break in the
shell, a sharp, horny
structure located near
the top of the beak.
This is referred to as
external pipping.
A Successful Hatch!
• Shortly after the
chick hatches its
down well dry and
fluff up The Chick
can be removed from
the incubator when
they are still wet if
they are placed in a
brooding area at 92 95 degrees F.
The Egg Tooth
• The egg tooth is only
present to help the
chick break from the
egg. Within 12 to 24
hours after the chick
hatches the egg tooth
will dry and fall off.
Care of Babies
• After the chicks hatch
you will have to keep
them warm. If they
peep too much, they
are cold!
• They are babies..they
will sleep a lot!
Care of Chicks
• Chicks need water and
feed after they are
• They will need a dry
place to stay in
• Enjoy your chicks!!
• The boy chickens have
shorter feathers than
the girl chickens.
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