We live in southwest Florida. Last night we had 14 out of 22 chickens killed. Feathers everywhere. 10 dead chickens left in the field and 4 missing. All dead chickens in-tack with minimal bites and no blood, except one was missing a head. Most had bit marks around neck, but some had bite marks on body. Bit mark picture attached, it seems like a small mouth but I am not sure. Our chickens are free range during the day and locked up at night. We forgot to shut the coop door. Feathers started in the coop and were all over the field. We have had this happen a few other times over the last 2 years, and it has been the same with MANY chickens killed, most bodies left, and some missing. Every time it has happened we had forgotten to shut the coop door, so of course we feel so bad. We have not had any problems with predators trying to get into the pen. Ordered a trail cam, but trying to figure out what got them. We also have two donkeys, but that didn't help at all. Any ideas?