They are living animals so anything is possible. I find my chickens are rougher with each other when getting into position on the roost for the night than at any other time. But if it is dark, they can't see to do anything after they are settled in. Turkeys are bigger than chickens and could do some damage if they wanted to. It is also possible a raccoon, possom, or member of the weasel family, just to name a few, are getting in there and killing them. You really did not give us much to go by. What do the bodies look like and what are your conditions. How secure are they.
