I have one rooster and five hens. One has always been broody and this year I decided to leave a couple of eggs to replenish. Only a single egg hatched and all seemed fine for about 3 weeks. I went out yesterday and one of the chickens had killed the baby chick that morning. The headless body was lying in the yard outside the coop. Does anyone know what would cause one of them to kill the baby? I did not separate Mom and baby from the rest, is that standard.