Birds and eggs

ok so it’s a dumb question…by what means do creatures born in eggs breath? In mammals the young receive oxygen in their blood through the mother but what about a chic crammed up in an egg?? Is there sufficient oxygen??

The eggshell is riddled with microscopic pores to allow air in. If you seal a living egg with wax, the chick inside will sufforcate.

All I need now is a ladder on a candle and do an experiment, I got a few nests in the yard. Take it easy animal activists…just kidding. Thanks for the reply!!

Yes, a bird or reptile egg has minute pores that are large enough to allow oxygen to diffuse in and carbon dioxide out. There is a special membrane within the shell called the allantois that functions like a lung to exchange gases for the embryo. (The allantois also stores waste from embryonic metabolism). One limitation on the size of the pores is that they can’t be too large or too much water vapor will diffuse out and the egg will dry out. The requirements for gas exchange provide an upper limit for how big an egg can get.

Egg membranes:

http://www.ucmp.berkeley.edu/vertebrates/tetrapods/amniota.html