There was a thread on here about a year or so ago where the same thing was happening to another person's chicks. BUT she had them in with guinea keets and discovered it was the keets that were doing it. You don't have keets in with yours, do you? I vote for what another poster said! Get a good book, some iced tea or wine and a lounge chair and go observe for a day. Could be you have one pecking the rest and haven't seen it. Rats make sense but, like you, I would think they would kill the chick and eat it unless they are running away from them when attacked??
