From an Egg -----to a Chick

V - 27

Objectives 1. Students will learn the parts of the egg.

2. Students will learn the changes that occur in the development of a

chick.

Grade Level 1-3 4-6

TEKS:

R- 1.1B,D,E;1.11A,B;1.17G;1.21B

R-

2.1B,D,E;2.7B;2.8A,B;2.10B;2.12D,E;

2.15C;2.17B

R- 3.1B,D,E;3.7B;3.8A;3.17C

S- 1.5A;1.6A,B;1.9A,B

S- 2.5A; 2.9A,B

S- 3.1A; 3.2A-E;3.9A

SS- 1.9A,B;1.18B

SS- 2.8A,C;2.10A,C;2.17C,D,E;2.18B

SS- 3.6A,3.16C,D,E,F

R- 4.10K;4.16B

R- 5.9A,E;5.10K;5.13C,D,E;5.16B;

5.21C

R- 6.9A,E;6.10K;6.13C,D,E;6.16B;

6.20C,D

S- 4.1A; 4.2A-E;4.8A,

S- 5.1A; 5.2A-E;5.9A;

SS- 4.6B;4.9B;4.13A,B;4.14B;4.22C

SS- 5.25C

SS- 6.21A,C

TAKS: GRADE OBJECTIVES

Reading

3, 4, 5, 6

1, 4

Writing

4

2

Science

5

1, 2

Math 1, 2, 3, 4, 5, 6

2, 4

Assessment Summary:

Objective 1: Students will fill in the blanks on "Parts of an Egg" diagram.

Objective 2: Students will write descriptive sentences or paragraphs after

observing outer and inner parts of an egg.

Background

Information: Included in Lesson

Materials: Eggs from grocery store

Fertile eggs

(County Extension Agent has

access to equipment, supplies and

instructions for incubating eggs)

paper plates

toothpicks

moist towelettes

Equipment: Hand lenses, Incubator

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From an Egg ---- to a Chick

Procedure

1. Introduce new vocabulary:

Grades 1-3 Grades 4-6

Embryo Albumen

Shell Yolk

Air Cell Chalazae

Membranes Clutch

Fertilize Pipping

Germinal disc

Activities

2. Make a memory game with the vocabulary words and their definitions. Use each word

in a sentence.

3. Complete "Egg to Chick Punctuation."

4. Complete " The Parts of an Egg" by reading and answering the questions.

5. Obtain fertile eggs and hatch chicks in an incubator. Incubating eggs adds much to the

students’ experiences in this lesson. Your county Extension Agent has a portable

incubator and access to fertilized eggs for use in the classroom and instructions.

6. In groups of two, have students observe outside of grocery store egg using hand lenses.

Pairs of students crack egg into paper plate and observe inside parts of egg. Compare

them to "Examining the Parts of an Egg" resource sheet. Have students write

descriptive sentences or paragraphs about their observations.

Fill in the names in the blanks on “Parts of an Egg” diagram. Use advanced “Parts of an

Egg” diagram for older students or as an extension activity.

7. Go to the website http://ag.ansc.purdue.edu/poultry/clipart.htm#Eggs and have

students examine the stages of embryo development. Compare the pictures on the

website with the diagrams in “Changes in Development of the Chick Embryo” and

determine as closely as possible the number of days of development.

8. Perform experiment "More White or More Yolk."

Embryology Websites of Interest

http://ag.ansc.purdue.edu/poultry/clipart.htm#Eggs

www.ext.vt.edu/resources/4h/virtualfarm

http://poultryweb.tamu.edu

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From an Egg----to a Chick

Many people wonder how and why eggs develop into chicks. You might wonder

why eggs from the supermarket don't grow and hatch when incubated. The male

chicken or rooster makes the difference.

The rooster must be present for an egg to be fertilized. Most eggs that you

buy at the supermarket are from hens that are raised without a rooster being

present. Roosters are not necessary at egg farms where eggs are produced for

consumption. Eggs for incubation are grown at special farms called breeder farms

where roosters are present with the hens.

Looking at the egg from the outside we see the shell, which is

a hard, protective covering made of calcium carbonate. The shell is

porous. (There are about 7,000 pores in a chicken eggshell.) This allows

the transfer of gases through 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.

Because the body temperature of a hen is approximately 106° F, eggs are very

warm at the time they are laid. The temperature of the air is usually much lower than

106° 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 egg.

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 medium in which the embryo develops, and it also

contains a large amount of the protein necessary for proper development.

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 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 called the germinal disc. The germinal disc is

where the female's genetic material is found. When an egg is fertilized the germinal

disc divides and develops into an embryo.

Naturally

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.

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The hen's body temperature is 105° F to 106° F. When the hen sits on the eggs,

she heats the eggs to 100° F to 101° 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 present on the grass.

The development of the chick begins in the single cell formed by the union of

two parental cells, egg and sperm, in the process known as fertilization. In birds,

fertilization occurs about 24 hours before the egg is laid.

The newly formed single cell begins to divide into 2, then 4, 8, 16, 32 and so on.

At the time of laying, hundreds of cells are grouped in a small, whitish spot (the

germinal disc) that is easily seen on the surface of the yolk.

When the egg is laid and cools, division of the cells ceases. After the egg is laid,

cooling the egg does not result in the death of the embryo. It may resume its

development after several days of rest if it is again heated by the hen or in an

incubator.

Functions of the Embryonic Membranes

Special temporary organs or embryonic membranes form within the egg, both

to protect the embryo and to provide for its nutrition, respiration, and excretion.

These organs include the yolk sac, amnion, and allantois.

The yolk sac supplies food material to the embryo. The amnion, by enclosing the

embryo, provides protection. The allantois serves as a respiratory organ, gets minerals

from the shell, and handles waste. These temporary organs function within the egg

until the time of hatching.

Hatching

Several changes take place during the 18th and 21st days. The chick draws

what remains of the yolk into its body and gets plenty of nourishment from it. Thus,

the chick really doesn't need to be fed for a few days after it hatches.

The chick's head is under its right wing with the tip of the beak pointed at the

air shell. The large neck muscle contracts and forces the egg tooth through the air

cell, and the chick takes its first breath. This is referred to as internal pipping. At

this time, you may hear the chick peeping inside the shell.

On the twenty-first day of incubation the chick finishes its escape from the

shell. The egg tooth makes the initial break in the shell. This is referred to as

external pipping.

The hatching process can last from 4 to 12 hours before the chick breaks free

from the shell. The chick, upon freeing itself from the shell, is wet and very tired. For

the next several hours it will lie still and rest. A few hours later the chick, now dry

and fluffy, will become extremely active and the egg tooth will dry and fall off.

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Activity 3

EGG TO CHICK PUNCTUATION

Put a capital letter and the correct end mark on each sentence.

1. the yolk is the yellow part of an egg

2. what is another name for the white part of an egg

3. wow, the chalazae is a neat part of the egg

4. the embryo is the baby chick before it is born

5. look at the baby chick hatching

6. the egg cell is the white spot on the egg

7. the chick grows from the egg cell

8. the chalazae are white twisted cords that hold the yolk

in place

9. how long does it take for a baby chick to develop inside

the egg

10. it takes 21 days for a baby chick to develop inside the egg

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Activity 4

The Parts of an Egg

The egg has four basic parts, the shell, the air space, the albumen and

the yolk.

The shell of the egg is the protective covering. It is porous, or has very

tiny openings which cannot be seen by the eye. The shell is cracked opened when a

baby chick hatches. Egg shells are not usually eaten by humans. The shells can be

used in composting to make soil rich.

The air space is a small pocket of air in the large end of the egg

between the shell and the albumen. It serves as a cushion for the baby chick or

embryo.

The yolk of the egg is what we call the yellow part. The yolk has a small

white spot on it called the egg cell or germinal disc. This is the part of the egg

from which the baby chick develops. The yolk provides food for the baby chick

while it is growing in the shell.

The albumen is the thick clear substance surrounding the yolk. It is also

called the egg white. Small white strands of material are found in the albumen.

These strands are called chalazae. They help suspend the yolk in the center of the

shell.

When we buy eggs at the grocery store they are usually infertile. This

means baby chicks will not develop inside them and hatch.

The poultry producer must keep close watch on his chickens to be certain

they are free from disease and are producing healthy eggs and chicks. If the eggs

are to hatch baby chicks, the poultry producer will follow the laying and hatching

process closely. He will depend on the workers in the poultry farm to monitor the

hens, making sure the hens are comfortable, well fed, free from disease, and safe

from animals which can harm or kill the hens. Other workers who might assist the

poultry producer are the veterinarian, county extension agents, and poultry

producer organizations.

V - 33

Activity 4

THE PARTS OF AN EGG

1.-4. What are the 4 main parts of an egg?

____________ ___________ ____________ ___________

5. Which part is the food for the unborn chick? _____________

6. The _____________ is the white spot on the yolk that

grows into a chick.

7. The _____________ hold the yolk in place.

8. What is the function of the air space? __________________

_______________________________________________

9. In this passage, infertile means __________.

O an egg will develop into a baby chick

O an egg will not develop into a baby chick

10. The eggs at the grocery store are usually infertile.

O true O false

V - 34

Activity 6

Examining the Parts of an Egg

We have all cracked a raw egg and felt its sticky white part. We have all seen the

yellow part of a boiled or fried egg. We may have even ordered our eggs fried sunny

side up with the yolk cooked very slightly.

Let’s take a look at an egg and identify the parts.

Before cracking the egg notice the tiny openings or pores in the shell. These pores

allow air and moisture to pass through the shell.

Crack the shell and gently empty the contents on to a paper plate. Use the diagram

to find and identify the parts of the egg.

chalazae

(shah-LAY-zee)

yolk

The white twisted cords

The yellow part that that hold the yolk

is food for the unborn in place.

chick.

egg cell albumen

The white spot on the The clear part around

yolk. The chick grows the yolk that holds

from the egg cell. water for the unborn

chick.

Diagram adapted from www.kidfarm.net

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Activity 6

Parts of an Egg

Fill in the blanks with the correct name.

The white twisted cords

The yellow part that that hold the yolk

is food for the unborn in place.

chick.

The white spot on the The clear part around

yolk. The chick grows the yolk that holds

from the egg cell. water for the unborn

chick.

Diagram Adapted from www.kidfarm.net

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Activity 6

Advanced

Parts of the Egg

Germinal Disc

Air Cell

Albumen or White

Chalaza Albumen or White

Vitelline Membrane Outer Membrane

Shell

Inner Membrane

Virginia Tech University Extension Service Virtual Farm

V - 37

Activity 6

Advanced

Parts of the Egg

Have students label the parts of the egg.

Virginia Tech University Extension Service Virtual Farm

V - 38

Activity 7

Changes in the Development of the Chick Embryo

Go to the website http://ag.ansc.purdue.edu/poultry/clipart.htm#Eggs

Compare the diagrams below with the pictures of embryo development on the

website and indicate the number of days of development for each diagram.

______ days

Mississippi State University Extension

V - 39

Activity 8

MORE YOLK OR MORE WHITE?

Question: Does an egg have more yolk or more white?

Hypothesis: I think the egg will have more .

Materials: 2 raw eggs

an egg separator

a clear glass

2 graduated cylinders

Procedure: Break 1 egg into the separator. Observe the amount of

white and yolk. Measure the amount of white by pouring

it into the graduated cylinder. Measure the amount of

yolk by pouring it into the graduated cylinder. Record the

readings.

Data: Measurements: yolk = ____mL white = ____mL

how many? yolk or white

Observations: The egg had mL more .

yolk or white

Conclusion: There is more in an egg.

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ANSWER KEY

ACTIVITY 3

Egg to Chick Punctuation

1. T .

2. W ?

3. W !

4. T .

5. L . or !

6. T .

7. T .

8. T .

9. H ?

10. I .

ACTIVITY 4

The Parts of an Egg

1.-4. (in any order) shell, air pocket,

yolk, albumen

5. yolk

6. egg cell

7. chalazae

8. The air space serves as a cushion

for the baby chick.

9. an egg will not develop into a baby

chick

10. true

ACTIVITY 6

Changes in the Development of

the Chick Embryo

4-6 days

9-11 days

14-15 days

19-20 days

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RESOURCES

CHILDREN'S BOOKS

Inside a Barn in the Country by Alyssa Capucilli

Thanks to Cows by Allan Fowler

The Egg--A Scholastic First Discovery Book

Cock-A-Doodle Dudley by Bill Peet

The Most Wonderful Egg in the World by Helme Heine

Chickens Aren't the Only Ones by Ruth Heller

TEACHERS’ BOOKS

The Amazing Milk Book by Catherine Ross and Susan Wallace