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Advanced Incubation and Embryology. Ken Koelkebeck U of I Extension Poultry Specialist kkoelkeb@illinois.edu. The Life of a Chick. Life begins with single cell formed by joining of two parent cells: ovum (yolk) and sperm = fertilization
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Advanced Incubation and Embryology Ken Koelkebeck U of I Extension Poultry Specialist kkoelkeb@illinois.edu
The Life of a Chick • Life begins with single cell formed by joining of two parent cells: ovum (yolk) and sperm = fertilization • Fertilization occurs about 24 hours before egg is laid • After fertilization, single cell beings to divide to 2, 4, 8, 16 cells and so on. This occurs on germinal disc/blastoderm
Chick Development • Cells begin to divide into segments during incubation • 3 segments - ectoderm - mesoderm - endoderm • Ectoderm – skin, feathers, beak, claws, nervous system, eye, mouth
Chick Development • Mesoderm – bone, muscle, blood, reproductive and excretory tracts • Endoderm – lining of digestive tract, secretory, respiration organs
Chick Formation • Extra-embryonic membranes of importance • 1) Yolk sac2) Amnion3) Chorion4) Allantois • Yolk sac – tissue layer growing over the yolk – digests and absorb yolk material
Chick Formation • Amnion • Fluid filled sac that surrounds embryo and serves as protection • Fluid allows embryo to move, change position, and shape • Fluid keeps embryo parts from sticking together
Chick Formation • Chorion • Serves to contain both amnion and yolk sac • No function at first, but then joins with allantois to form chorio-allantoic membrane • Allows calcium reabsorption through capillaries of allantois from the shell
Chick Formation • Allantois • Serves as respiratory organ for embryo • Holds excretions from embryo • Absorbs albumen (nutrient protein) for embryo • Absorbs calcium from shell for embryo • Allantois origin within body of embryo
Embryonic Blood Vessels • One – vitelline vessels carry yolk material to embryo • Two – allantoic vessels – respiration and waste material
Hatching Days 19 & 20 - Abdominal wall surrounds yolk sac - Chick withdraws rest of yolk into body - Fluid decreases in amnion Day 21 - Chick forces egg tooth through air cell- head under right wing takes first breath – internal pipping – chick peeping inside
Hatching • Day 21 - Egg tooth breaks through shell – external pipping • Process last from 4 to 12 hr • Chick emerges very wet, tired and rests for several hr • After exiting shell, egg tooth (beak) dries and falls off