Sandhill Crane (Grus canadensis) chick in the process of hatching. The egg tooth, a small, sharp, cranial protuberance used  to break or tear through the egg's surface during hatching is visible. <br />
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Chicks have a pipping muscle on the back of their necks. It gives them the strength to force the egg tooth through the inner membrane of the eggshell.<br />
When a chick becomes too large to absorb oxygen through the pores of its eggshell, it uses its egg tooth to peck a hole in the air sac located at the flat end of the egg. This sac provides a few hours worth of air, during which the chick breaks through the eggshell to the outside. The egg tooth falls off several days after hatching.
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Sandhill Crane-Vyn-110709-11414.jpg


Sandhill Crane (Grus canadensis) chick in the process of hatching. The egg tooth, a small, sharp, cranial protuberance used to break or tear through the egg's surface during hatching is visible.

Chicks have a pipping muscle on the back of their necks. It gives them the strength to force the egg tooth through the inner membrane of the eggshell.
When a chick becomes too large to absorb oxygen through the pores of its eggshell, it uses its egg tooth to peck a hole in the air...
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