I found one chick dead that a hen hatched around 8 weeks ago. There were three that hatched. The other two seem to be doing fine. Their mother is still with them. I hadn't observed any overly aggressive behavior toward any of the chicks by the other chickens (all hens). The dead chick did always seem to be behind the other chicks in development and appeared to be a rooster. I found the dead chick with its badly damaged head sticking out through the fence like it had been trying to get away from the other chickens. Could they have killed it because it was sickly or because it was a rooster? I don't have any other good explanation for the cause of death unless it died with its head sticking out of the fence and a crow came by and picked it.