What’s an egg tooth?

I get asked a lot of chicken and poultry questions, sometimes face to face, sometimes over email or the phone and I’ve even had the odd letter too. I don’t mind, I enjoy chatting about chickens and enjoy even more listening to other peoples experiences – you never stop learning in life, it’s just much of what I learn and retain these days tends to be covered in feathers.

One recent question was what’s an egg tooth and how is it used. First off the ‘egg tooth’ is a small, sharp temporary cap that sits on the end of the beak of a chick. Most people probably associate it with chicks ability to break out of the egg shell however thats only a part of the story.

The egg tooth develops whilst the chick is within the egg and is primarily used to help the chick break into the air sac within the egg. Egg shells are porous and allow the movement of oxygen into an egg but towards the end of the incubation period this flow of air is insufficient for the chick to ‘breathe’. The chick, using its egg tooth, will then break through the membrane of the egg and into the air sac where sufficient oxygen can be found. It is then that the chick will use the egg tooth to break out of the shell, known as pipping.

Never seen an egg tooth? If you look at the picture of the day old lemon cuckoo pekin you will see the egg tooth as a light cap at the end of the beak. Within a few days this tooth will fall off as it’s no longer required.

The egg tooth on a day old Lemon Cuckoo Pekin