How does the chicken's body create the egg? is it like the sac that babies are in?

Question

and why doesn't it crack in her body?

Answer 1

The egg develops the same way that any female vertebrate produces eggs, similar to the egg you ovulate every month. The eggs are produced in the ovaries just like other vertebrates. The hen is on a cycle of ovulation and release of her eggs. If the egg has not been fertilized it releases upon menstruation. The unfertilized egg develops its shell prior to release into the cloaca, this is the orifice birds and most reptiles release their solid and liquid wastes as well as functions as a reproductive opening.

The structure babies develop within is termed the placenta and it is produced by the fetus during the first stages in development