How sure are you that it was another chicken, or even an adult chicken? Many predators go for the head first, both to kill and to eat. Weasels and birds of prey immediately come to mind, thinking of a chick versus an adult chicken because so little was eaten. I could see a small hawk or a...
What I suggest is that you build someplace where you want them to sleep at night and house them there about a week. That will get them used to going to bed there. Normally that is inside the coop. I will also give the adults some up-close time with them in the morning while they are still...
I like June’s post. I do things a little differently but the results are similar.
My brooder is in the coop with the adults. The chicks grow up with the flock but are protected from the adults. Sometimes I just open the brooder door at five weeks and let them mingle. Sometimes I move them...