I butchered 14 Cornish X chickens last weekend. We had noticed weeks ago that one cockerel had a large pinkish swelling at his rear end. Not knowing what this was, I butchered him last, which happens to have been in the dark with a porch light.....yeah, I was desperate to finish these birds up. After plucking, I found a massive scar on his breast near the swelling. When I opened his back end for gutting there was NO abdominal wall....the intestines were right there. The gizzard was attached to the cartilage at the end of the keel bone. There was no fat in this bird either, despite the fact he was a 8 lb bird. Here is a picture of the carcass showing the scar. Did he blow out his rear end growing too fast?