I have been raising my Cornish slow broilers (5 weeks old) with my buff orpingtons (7 weeks old) in a tractor that I move every day. Yesterday I came out to find three dead BOs, with their heads and necks eaten away, and blood smeared on a few of the CRs. There is no evidence that a predator got inside, so I am assuming that this is a case of cannibalism. I felt that the birds had plenty of space, though with the recent rain, they may have been crowded on the roost to stay dry. The CRs are two weeks younger than the BOs, but surpassed them in size last week. Ive also noticed a lot of posturing recently. (breast bumping and wing flapping at each other.) I have separated them and moved the BOs, but do not know if that will solve the problem. If you have any ideas of what may have happened, Id appreciate hearing them.