1. Chicken Egg Development
Taken and edited from Matt Patton’s CTEOnline lesson chicken embryo development

2. Day 1 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.
Explain the process of how it works and what the machine does

3. Day 2 25 hours: The heart begins to form.
33 hours: The ears begin to form.
42 hours: The heart starts to beat.
Explain the process of how it works and what the machine does

4. Day 3 The head begins to turn onto its left side.
The tongue begins to form.
The amnion completely surrounds the embryo.
The tail has appeared.
Wing and leg buds are visible.
Soon other organs such as the liver, kidneys, and lungs will appear.
Explain the process of how it works and what the machine does

5. Eye Pigmented The toes begin to form. Day 4
Explain the process of how it works and what the machine does

6. Day 5 The reproductive organs begin to form.
The bones of the legs begin to form.
The crop begins to form.
Explain the process of how it works and what the machine does

7. Day 6 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.

8. Day 7 A row of feather germs appears on the tail.
The sclera of the eye begins to form.
Feather papillae appear on the thigh.
The leg bends at the knee.

9. Day 8 Three rows of feather germs are visible on the tail.
The nictitating membranes (inner eye lids) begins to form.
The egg tooth begins to form.
The bone marrow cavity of the femur begins to form.
Explain the process of how it works and what the machine does

10. Day 9 Upper eye lids begin to cover the eyes.
The knee caps begin to form.
Explain the process of how it works and what the machine does

11. Day 10 Claws begin to form. The comb is visible.
Flight feathers appear.
Feather tracts appear over the sternum.
Lower eyelids develop.
Explain the process of how it works and what the machine does

12. Day 11 The toe claws begin to curve downward.
The bottom of the feet become padded.
Feather germs on the back and tail appear as long, tapering cones.
The beak begins to harden.
The comb appears serrated.
The embryo begins to draw
calcium from the eggshell for
its growing bones.
Explain the process of how it works and what the machine does

13. Day 12 Scales appear on the lower legs.
The embryo continues to grow and move.
The ribs begin to ossify.

14. Fingers of the wings are covered with feather papillae.
Day 13
Fingers of the wings are covered with feather papillae.
The left and right collar bones fuse to form the wishbone.
Explain the process of how it works and what the machine does

15. Day 14 The embryo turns its head toward the blunt end of the egg.
The skull has begun to ossify.
Explain the process of how it works and what the machine does

16. The scales, claws, and beak are becoming firm.
Day 15
The scales, claws, and beak are becoming firm.
Explain the process of how it works and what the machine does

17. Day 16 The embryo turns its beak toward the air cell.
The chorioallantoic cavity lines most of the inside surface of the egg shell.

18. The beak turns towards the air cell.
Day 17
The beak turns towards the air cell.
Explain the process of how it works and what the machine does

19. Growth of embryo nearly complete Yolk sac is still outside the embryo
Day 18
Growth of embryo nearly complete
Yolk sac is still outside the embryo
Head is under right wing
Explain the process of how it works and what the machine does

20. Day 19 Yolk sac draws into the body cavity Amniotic fluid gone
Embryo occupies most of the space within the egg (not in the air cell)

21. Day 20 Yolk sac completely drawn into body cavity.
Embryo becomes a chick (breathing in air cell)
Internal and External pip
Explain the process of how it works and what the machine does

22. Day 21
HATCHES
Explain the process of how it works and what the machine does