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Chick Embryology.

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Presentation on theme: "Chick Embryology."— Presentation transcript:

1 Chick Embryology

2 What are the proper terms used in describing poultry?
Poultry is the group name for all domesticated birds used for meat, eggs, or feathers. A baby chicken of either sex is a chick. A young male chicken is a cockerel. A castrated (neutered) male chicken is a capon. A mature male chicken is a rooster. A young female chicken is a pullet. A mature female chicken is a hen. A group of chickens is a flock.

3 What are the proper terms used in describing poultry?
A. Chickens are classified as layers or broilers. Layers are chickens used to produce large quantities of eggs. On average layer hens produce 250 to 270 eggs per year. Broilers are six- to seven-week-old chickens weighing about 4 pounds that are used for meat because they are tender.

4 What are the different, breeds, and varieties of chickens?
We have two breeds of chicken in our incubator: 1. The White Leghorn. The Leghorn is the most popular layer breed in the United States. This breed is also known for its ability to take flight. Leghorns produce white eggs. They express yellow skin, yellow shanks, white earlobes, and reddish-bay eyes. They are somewhat smaller than most breeds, and tend to be noisy. The chicks are white in color.

5 What are the different, breeds, and varieties of chickens?
2. Rhode Island Red The Rhode Island Red is a dual-purpose breed; that is, it is raised for meat and eggs. The breed is dark red and lays brown eggs. Rhode Island Reds have yellow skin, yellow shanks, red earlobes, and reddish-bay eyes. Chicks are a light red to tan color with two dark brown bars running down their backs.

6 How does the process of fertilization take place in a chicken egg?
The yolk is released into the oviduct (a long, spiraling tube in the hen's reproductive system), where it can be fertilized internally (inside the hen) by a sperm. Fertilization of a chicken egg takes place when the sperm unites with the egg, forming the blastoderm. Unfertilized eggs will go through the same process however, it will form a blastodisc. A blastodisc will not be a dark white Not symmetrically round

7 Can an un-fertilized egg develop an embryo?

8 Can an unfertilized egg actually develop?
Parthenogenesis is an inherited trait that causes the development of unfertilized eggs. About 1% of parthenogenetic embryos will develop and hatch with deformities. Parthenogenesis is more common in turkeys than in chickens.

9 What are the internal parts of an egg and what are their functions?
1. Blastoderm/blastodisc 2. Yolk: Produced by the hen's ovary in a process called ovulation. It is the yellow, inner part of the egg where the embryo will form. The yolk contains the food that will nourish the embryo as it grows.

10 What are the internal parts of an egg and what are their functions?
3. Vitelline (yolk) membrane - the membrane that surrounds the yolk. 4. Thick albumin - the stringy part of the egg white (albumin) located nearest the yolk. 5. Thin albumin - the watery part of the egg white (albumin) located farthest from the yolk. 6. Chalaza - a spiral, rope-like strand that anchors the yolk in the thick egg white. There are two chalazae anchoring each yolk, one on the top and one on the bottom.

11 What are the internal parts of an egg and what are their functions?
7. Inner shell membrane - the thin membrane located between the outer shell membrane and the albumin. 8. Outer shell membrane - the thin membrane located just inside the shell. 9. Air cell - an empty space located at the large end of the egg; it is between the inner and outer shell membranes. 10. Shell - the hard, protective coating of the egg. It is semi-permeable; it lets gas exchange occur, but keeps other substances from entering the egg. The shell is made of calcium carbonate.

12 Label the Chick Egg

13 What is the ideal environment for incubating eggs artificially?
Four Factors must be present for ideal incubation conditions: A. Temperature. Optimum temperature for hatching chickens is between 99 and 100 degrees F. B. Humidity. Eggs lose moisture during development and low humidity causes an increased loss. High humidity can prevent the correct evaporation of water.

14 What is the ideal environment for incubating eggs artificially?
C. Ventilation. Proper circulation is critical to assure a fresh supply of oxygen and removal of carbon dioxide. D. Position and turning of eggs. The head of the chick must face the large end of the egg for proper hatching. Eggs should be incubated large end up, and turned three to five times daily to prevent the developing embryo from attaching to the shell membrane.


16 How do we prepare eggs for hatching and care for young birds during brooding?
Fertility of eggs can be determined by a process known as candling. A. Eggs held up to an egg candler, a device for shining a light beam into an egg. Eggs will look different depending on fertilization or lack of fertilization. Fertile eggs will appear darker as the developing embryo begins to form. Infertile eggs can be detected after 15 to 18 hours of incubation.

17 Between the following poultry species, who has the longest incubation period? Shortest?
WHY? Duck Pigeon Ostrich Chicken Turkey

18 Different breeds of poultry have different incubation lengths:
How do we prepare eggs for hatching and care for young birds during brooding? Different breeds of poultry have different incubation lengths: Do not candle or turn the eggs the last three days of incubation. Bird: Incubation: Chickens 21 days Ducks/Turkeys 28 days Pigeon 18 days Ostrich 42 days

19 Chick Development DAY 1 18 hours – the digestive system starts to appear 20 hours – the vertebral column starts to appear 21 hours – the nervous system and brain begin to form 22 hours – the head begins to form 23 hours – the extraembryonic blood systems begin to form 24 hours – the eyes begin to form DAY 2 25 hours – the heart begins to form 35 hours – the ear pits begin to form 37 hours – the amnion starts to appear 42 hours – the heart starts to beat 46 hours – the throat begins to form

20 Chick Development Day 4 The tongue begins to form The tail appears
50 hours – the amnion begins to form 60 hours – the nose begins to form 62 hours – the legs start to appear 64 hours – the wings start to appear 70 hours – the allantois begins to form Day 4 The tongue begins to form The tail appears The toes begin to form Extra-embryonic circulation is fully functional DAY 5 - The crop begins to form - The bones of the legs begin to form - The sex of the chick is determined and its reproductive organs begin to form(ovary & oviduct for the female as studied in Part III)

21 Chick Development Day 6 The beak and egg-tooth begin to form Day 7
The ribs start to appear The gizzard begins to form Voluntary movement begins Day 7 The wings bend at the elbow and the leg at the knee The toes are visible The abdomen is bigger as the intestine starts to loop

22 Chick Development Day 9 The mouth opening appears Day 8
The claws begin to form Day 8 The feathers begin to form The eye lids begins to form

23 Chick Development Day 11 The toe claws begin to curve downwards
The bottom of the feet become padded The chick begins to take calcium from the eggshell Day 10 The beak starts to harden The comb is visible The flight feathers develop

24 Chick Development Day 12 Scales appear on the lower legs
The chick continues to grow and move Day 13 Body fairly well covered with feathers The left and right collar bones join to form the wishbone

25 Chick Development Day 14 Day 15 The embryo turns its head towards
the large end of the egg The skull and ribs have begun to ossify Day 15 The scales, claws and beak are becoming firm

26 Chick Development Day 16 The chick is fully covered with feathers
The albumen is nearly gone and the yolk is increasingly important as nourishment Day 17 The chick turns its beak towards the air cell and begins preparation for hatching

27 Chick Development Day 18 The growth of the embryo is nearly complete
The amnion which protects the chick begins to disappear Day 19 The yolk sac begins to enter the body The chick occupies all the space in the egg except the air cell

28 Chick Development Day 20 The yolk sac is completely drawn into the body The beak breaks through the inner shell membrane The lungs begin to function and to use the air cell for breathing The allantois ceases to function and starts to dry up Day 21 The neck begins to jerk The egg tooth pips through the shell The chick hatches!

29 How the chick hatches When the chick is completely out of the shell it lies still. It is extremely tired. After a rest it begins to rise to its feet and gain coordination. Within a few days the egg tooth will disappear.

30 What is the process of chick development during incubation?
Day 3: Body parts have begun to for The embryo will have a distinct question mark shape Heart begins to beat Day 6 Voluntary movement begins formation of reproductive organs and differentiation of sex Day 9 Egg tooth begins to form Body parts can be clearly recognized

31 What is the process of chick development during incubation?
Day 12 Beginning of feathers Day 16 Beak, claws become to harden Embryo continues to grow and moves into position to break the shell Day 20-21 yolk sac completely drawn into body cavity; embryo occupies practically all the space within the egg except the air cell When the air cell is broken, the embryo only has a limited time to pip its way out of the egg.

32 What is the process of chick development during incubation?

33 How do we prepare eggs for hatching and care for young birds during brooding?
D. Brooding refers to the care of young poultry from the time of hatching through eight to ten weeks of age. Chicks should be removed from the incubator when they have dried and the down becomes fluffed. This drying normally takes about 12 hours. 1. Certain environmental conditions are needed for proper brooding. a. Temperature—When chicks are one day old, the temperature should be between 90 and 95 degrees F. The temperature is generally lowered five degrees per week until a temperature of 70 to 75 degrees is reached, or until the chicks are fully feathered. b. Ventilation—Proper ventilation provides fresh oxygen, removes carbon dioxide, carbon monoxide, ammonia, and keeps bedding dry. c. Moisture—50 to 60% relative humidity is recommended for good feathering.

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