Most commercial breeds have had the broodiness bred out of them. If you kill any hen that goes broody, after a while you have hens that pass on the trait to not go broody to their offspring. In commercial operations it is a hen's job to lay eggs. They have incubators to hatch the eggs. Hatcheries are commercial operations.
It is relatively rare for certain breeds or crosses to go broody, but it does happen. There have been two or three threads on here that I've seen the last week about sex links successfully hatching and raising chicks. It is hard to totally defeat nature.
