Here are the basics. I've had chickens in an old wood shack for about a year & haven't lost a single one. They are confined 24/7, but have lots of room, plenty of light & optimum conditions. The floor & bottom walls are secure & tight, however, there are(were) a few small holes in a couple of the roof corners... we're talking maybe 5x5 inches. I always had intention to board 'em up, but never got around to it... needless to say, they got boarded up this morning. Whatever got in had to climb up about 10 feet on the side of the wood building, crawl through the hole in the upper corner, kill the bird on the coop floor, and get back up & out. The hen was eaten on above the tail section, but just minimally--through the skin, down to the cavity... everything else intact. I butchered a hen last week that had similar activity on the same part of her body, but she was still alive. She was always at the bottom of the order and pecked on alot, and honestly just thought the other chickens had done this to her. I found what looked like to be some coon tracks outside, does this sound like the work of a coon? Large rat? Would one of those gnaw on a chicken over several days until it killed it? I think I've covered up all the sizeable holes, but it's an old building, and it's hard to seal up every crack.