I copied this info from SU Hawk's Twitter account so you'll have to READ IT FROM THE BOTTOM UP. I thought it was very interesting. I still don't understand how the egg yolk gets in the chicks belly tho.
4/20 When the embryo/hatchling, emerges from the egg, its down is damp & matted. Its closed eyes are large & bulging. You will say Awwww!
4/20 Then the egg yolk moves to the stomach for digesting. & continues to nourish the hatchling through the first 24 hours of its life
4/20 During hatching, the egg yolk is retracted into the hatchling's abdominal cavity through the “yolk stalk” into the small intestine.
4/20 After several weeks, the egg tooth is absorbed by the beak or wears off and the hatching muscles shrink in size on the back
4/20 The force of the egg tooth creates a pip & the hatchling uses its newly developed head & legs to move and force the egg to break
4/20 By contracting its hatching muscles, the hatchling forces the egg tooth against the shell wall.
4/20 A special "hatching muscle" on the back of the embryo's neck assists in the pipping process allowing the hatchling to break the shell
4/20 This is hard work & may take 24 hours or more for the hatchling to break the shell and push the top off. This is called breakup.
4/20 The embryo/hatchling will rotate within the egg counterclockwise & will continue to break all the way around the egg w/ the egg tooth
4/20 The egg tooth is a small bit of keratin located on top of the beak which is already formed and is used to crack or "pip" the shell
4/20 Then within about 48 hours of "draw down" the embryo/hatchling starts breaking the egg shell (pip) with the egg tooth.
4/20 Breaking into the air cell will be the first time the embryo/hatchling will use its lungs to breathe air.
4/20 The air cell at the large end of the egg gets larger and the embryo breaks through a membrane to enter that air cell.
4/20 The hatching process starts with what is called draw down. egg.JPG - Bild entfernt (keine Rechte) Drawing courtesy of Michael Walters
13:20, 4/20 SU-Sue stands to stretch & preen. Pip visible on the front egg. Pip Pip Hooray!!
Maybe this site will help: http://extension.psu.edu/animals/poultry...-within-the-egg "The yolk sac is a layer of tissue growing over the surface of the yolk. Its walls are lined with a special tissue that digests and absorbs the yolk material to provide sustenance for the embryo. Yolk material does not pass through the yolk stalk to the embryo even though a narrow opening in the stalk is still in evidence at the end of the incubation period. As embryonic development continues, the yolk sac is engulfed within the embryo and is completely reabsorbed at hatching. At this time, enough nutritive material remains to adequately maintain the chick for up to two days."
Odin and EJ's last chick survived longer than the chicks hatched earlier. Odin went missing on 18th, Last chick hatched on 20th and died the night of the 21st. :( I am sure the yolk sac provided the nourishment for that chick.
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Thu Apr 20, 2017 4:36 pm
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