Exploring Poultry and Poultry Products Part II Unit 2 Animal Science

For eggs to hatch they must first be fertilized and incubated. OBJECTIVE 4: Understand the parts of an egg and the development of the embryo. For eggs to hatch they must first be fertilized and incubated. Chickens will lay eggs even if they are not fertilized. The non-fertilized eggs are the ones you can buy at the store.

OBJECTIVE 4 continued A. The length of time for an embryo to develop in an egg varies by species. 1. Chickens need 21 days. 2. Geese need 29–31 days. 3. Turkeys need 27–28 days. 4. Ducks, depending on their species, need 28–35 days.

B. There are seven major parts of an egg. 1. Shell -the outer covering of the egg that protects the inside. The shell is made up of mostly calcium carbonate. 2. The shell membrane is actually two very thin linings that protect harmful contaminants like bacteria from entering the egg. 3. The air cell, or pocket, forms at the large end of the egg and grows larger as the embryo (developing baby chick) gets larger.

OBJECTIVE 4 continued 4. The yolk is the center, yellow part of the egg that provides nourishment for the developing embryo. 5. The blastodisc is the area where the embryo will begin to grow if the egg is fertilized. When the egg is fertilized, this area is called the blastoderm. 6. The albumen is the egg white or clear part of the egg. It cushions the embryo as it grows and gives it protein. 7. The chalaza is the curly cord that holds the yolk in the middle of the egg.

CHICKEN EGG INTERNAL STRUCTURES OBJECTIVE 4 continued CHICKEN EGG INTERNAL STRUCTURES

DEVELOPMENTAL STAGES OF A CHICK EMBRYO OBJECTIVE 4 continued DEVELOPMENTAL STAGES OF A CHICK EMBRYO