4H Embryology Mrs. Hayes

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Chicken Trivia Chickens are birds Chickens are birds – Chickens have two waddles – Chickens have a comb Hens are female chickens Hens are female chickens Roosters are male chickens Roosters are male chickens Chickens have navels Chickens have navels Chickens need to eat gravel Chickens need to eat gravel Chickens have earlobes Chickens have earlobes – Indicate an egg’s color Picture from Moyer’s Chicks, Inc. – Moyer’s Broiler/Roaster Chicks

Free Range Chicken Farms

Industrial Chicken Farms

A chicken embryo growth span is... Twenty-one days Twenty-one days

Embryo Growth – Day 1 Germinal spot grows and cells begin to split into specific types of cells Germinal spot grows and cells begin to split into specific types of cells Picture courtesy of Phillip J. Clauer, Penn State 4-H Embryology in the Classroom Web Resource, Fertilized verse Non Fertile

Embryo Growth – Day 3 Question mark-shaped embryo visible Question mark-shaped embryo visible Blood vessels on yolk sac defined Blood vessels on yolk sac defined Brain, head, and beating heart visible Brain, head, and beating heart visible Amnion complete Amnion complete Picture from The Sacramento Zoo — E Feature: Egg Development; Artwork from North Carolina Extension Service

Embryo Growth – Day 5 Eye and organs formed Eye and organs formed Sex of the embryo is known Sex of the embryo is known Day 6 – 7: Embryo will begin to move and resemble a chick Day 6 – 7: Embryo will begin to move and resemble a chick Picture from The Sacramento Zoo — E Feature: Egg Development

Embryo Growth – Day 10 Bones and beak harden Bones and beak harden Skin pores and down feathers visible Skin pores and down feathers visible Picture from The Sacramento Zoo — E Feature: Egg Development

Embryo Growth – Day 15 Scales, claws, and feathers complete Scales, claws, and feathers complete Small intestines taken into body Small intestines taken into body Albumen nearly gone Albumen nearly gone Turns head toward large end of egg Turns head toward large end of egg Picture from The Sacramento Zoo — E Feature: Egg Development

Embryo Growth – Day 19 Growth complete Growth complete Shell is full – except the air cell Shell is full – except the air cell Day 20 Day 20 – Embryo breaks into air cell and takes first breath – Yolk sac is completely drawn into abdomen Picture from The Sacramento Zoo — E Feature: Egg Development

Egg Tooth The egg tooth is only present to help the chick hatch. Within 12 to 24 hours after the chick hatches the egg tooth will dry and fall off. The egg tooth is only present to help the chick hatch. Within 12 to 24 hours after the chick hatches the egg tooth will dry and fall off. Picture courtesy of Phillip J. Clauer, Penn State 4-H Embryology in the Classroom Web Resource, Hatching

Embryo Growth – Day 21 Chick will pip at the shell until it hatches Chick will pip at the shell until it hatches Not an immediate process -- 8 to 12 hours Not an immediate process -- 8 to 12 hours Should not assist chicks with their hatching Should not assist chicks with their hatching Egg tooth visible for a day or two after hatching Egg tooth visible for a day or two after hatching Picture from The Sacramento Zoo — E Feature: Egg Development

Male or female? For only the first day or two For only the first day or two – Males: short, fluffy wing feathers – Females: longer, more distinct wing feathers Picture courtesy of Phillip J. Clauer, Penn State 4-H Embryology in the Classroom Web Resource, Hatching

Farm Hatching Hen lays an egg, one per day, until she has a group of 8 to 13 eggs, called a clutch Hen lays an egg, one per day, until she has a group of 8 to 13 eggs, called a clutch She will sit on her clutch all the time, except for leaving for food and water She will sit on her clutch all the time, except for leaving for food and water Her body heat warms the eggs to 100°F - 101°F Her body heat warms the eggs to 100°F - 101°F She provides humidity by bringing back moisture from the environment on her legs and feathers She provides humidity by bringing back moisture from the environment on her legs and feathers She turns the eggs on a regular basis by scooping and rolling them with her beak She turns the eggs on a regular basis by scooping and rolling them with her beak

Classroom Hatching Incubator replaces hen Incubator replaces hen – Eggs need to be kept between 99°F and 101°F Control temperature with a thermostat and thermometer Control temperature with a thermostat and thermometer Control humidity by adding room temperature water once a day Control humidity by adding room temperature water once a day – Balances the moisture that escapes through the shell’s pores – Humidity fluctuations can cause the chicks to stick to their shells Control rotation by gently rolling the eggs onto their opposite side three times a day until the end of Day 17 Control rotation by gently rolling the eggs onto their opposite side three times a day until the end of Day 17 – Turning the eggs allows the embryos to not rest on one side for too long and stick to the shell or cause developmental defects

Brooding box A box, tank, or cage that will keep the newly hatched chicks safe and warm and allow access to food and water A box, tank, or cage that will keep the newly hatched chicks safe and warm and allow access to food and water Prepare the brooder before the chicks hatch Prepare the brooder before the chicks hatch

Handling Always remember to wash your hands before and after handling the chicks Always remember to wash your hands before and after handling the chicks Always remember that the chicks are babies Always remember that the chicks are babies Always hold them gently by cupping them in your hands Always hold them gently by cupping them in your hands Always hold them over a table or at floor level Always hold them over a table or at floor level