So, I go to check on everyone last night, and find the barn cat, in the coop, curled up next to the water warmer. I can only think that she got in when I was filling the feeder, and, because it was dark, I didn't notice her. The chickens didn't seem to be paying her any attention, and she was leaving them alone, so I just left her in there. I had no idea chickens had slumber parties. I hope Patches doesn't invite them over, because I'll probably have to disappoint them and say no.