Poultry
This publication shows the development of a chicken embryo from Day 1 through Day 21.
- Hatching eggs.
- Infertile, unincubated egg. Blastodisc located on top of yolk appears irregular in shape.
- Fertile, unincubated egg. Blastoderm larger, more regular in shape and has a “donut-appearance.”
- Day 1 “Donut-shape” greatly enlarged and embryo lies within the donut ring.
- Day 2 Blood appears as “blood islets” in outer ring of developing embryo.
- Day 3 Circulatory system well developed. Formation of appendages.
- Day 4 Notice brain to body size relationship.
- Day 5 Brain continues to develop at rapid rate.
- Day 6 Wing development rapid. Development of egg tooth begins.
- Day 7 Egg tooth seen on tip of beak. Eyes very conspicuous.
- Day 8 Feather tracts seen on the back. Wings, feet, toes well developed.
- Day 9 Beginning formation of feathers.
- Day 10 Down feathers appear. Hardening of beak and egg tooth begins.
- Day 11 Eyelids have overgrown eyes.
- Day 12 Calcification of bone started. Toenails and down feathers on neck, thighs and wings present.
- Day 13 Appearance of scales on legs. Comb and wattles present.
- Day 14 Embryo acquires a more chick-like appearance.
- Day 15-19 Embryo grows rapidly assuming hatching position with the head under the right wing and beak toward the air cell. Remaining yolk sac begins entering body cavity.
- Day 20 Chick begins pipping through shell.
- Day 21 Chicks hatch and dry.
Kenneth S. Macklin, Extension Specialist, Professor; John P. Blake, former Extension Specialist; Joseph B. Hess, former Extension Specialist; Wallace D. Berry, Associate Professor; Robert A. Voitle, Professor Emeritus, all in Poultry Science at Auburn University; and Thomas A. Hess, Biological Sciences/Wildlife and Forestry, Auburn University
Reviewed June 2022, Chicken Embryo Development, ANR-1408