What if you find all your adult birds dead at once, all 18. In a coop, in varying stages of... remains. Some just bloody and nearly intact, some with a few parts missing, some nearly only feathers left, and some mush. Seriously, it looked like a horror movie was filmed in our coop. The chicks, in the adjacent connected building were untouched.
More than likely coons, probably not just one. We had a similar event, 5 of 7 were destroyed. Have since caught 5 coons and 4 skunk in hav-a-heart traps.