This question has been bugging me for quite some time. I watched a thing on PBS about incubation in hatcheries (you know the assembly line methods). Anyway, I noticed they poke a hole in the air sac end of the egg when they remove from the turners....Why is that? Is it so they get a more successful hatch because the chicks actually have fresh air coming into the air cell or what? I think they are giving them the mareks shot but still just interesting why they do that.