As Rare as Hen's Teeth

Well the hen may not have teeth, but every chick certainly does!  The egg tooth is  small and sharp and is found on the tip of the beak of every chick - it is what the chick uses to break out of its shell (a process called "pipping").   It only lasts a day or two, being resorbed into the beak shortly after hatching.



 

Day of hatching. The egg tooth
is the white protuberance with a
tiny sharp point on the top side
of the beak

2 day old. Pretty much gone.

Day old.  Going .....

When I saw the egg tooth on my recently hatched Barnevelder chicks, I thought I would try and find out more about them. The egg tooth actually plays a very important role in the entire hatching process, and its not just about breaking out of the shell.

This is what I found:

The incubation period for a chick is 21 days. Around the 15th day, the chick  starts to turn so that its head is  at the flatter end of the egg, where the air sac is.  It is now too large to absorb enough oxygen through the pores of the eggshell, so uses its egg tooth to break through the inner membrane, and the chick's lungs begin to function. The air sac provides it with enough air for the next stage, when the hatching begins in earnest at around the 20th day. With a special muscle in its neck, developed just for this purpose, the chick uses his egg tooth again to peck at the shell repeatedly until the shell cracks.  Exhausted, it stops pipping for three to eight hours and rests. During this time, its lungs are functioning fully and are adapting to the outside atmosphere while the chick prepares for the next stage of pipping.

As the chick works away at pipping the shell, it turns slowly inside the egg.  Eventually, as it cuts its way around the shell, it begins pushing on the flat end of the egg. After 40 minutes or so of intensive activity, the chick breaks free from the shell with a final burst of energy.
When the chick is freed completely from the shell, it lies still. Its energy has been virtually exhausted, and it is extremely tired. After a while, the chick begins to rise to its feet and gain coordination of its muscles and fluff out its downy covering.



One of our 3 Barnevelder
chicks a few hours after hatching

This explains a lot about the process of hatching.  The pipping, the struggles, the resting, more pipping and more struggles are integral to the development of the lungs, circulation and muscles of tiny chick and its preparation for entry into the world.  It makes it plain how important it is that we don't intervene in the process unless something is clearly going wrong, or if one of the steps is taking too long. For example, on one of our earlier hatches, we had a chick that was the first of the clutch to start pipping, but still hadn't hatched when all the others had.  It died inside the shell.  I think now that some timely intervention may have saved it.

So there you have it.  The incredibly important tooth that every chick has, but you've got to be quick to see it!

Chief source of information: http://chickscope.beckman.uiuc.edu/resources/egg_to_chick/procedures.html

Till next time,
Lesley