I'm going to say skunk or raccoon because, a weasel would have left the whole body there. A coyote would not have been able to get in by the sounds of it. Raccoons and or skunks are not always nocturnal and raccoons in particular are crafty little buggers, and will figure out a way in. When I growing up we had a raccoon break a window(it had a very small hole in it from hail) and literally ripped a hole into the wall to get in the side of the coop where the chickens were. (It was a 2 room coop, one of this with a small roof over the front and a taller roof on the back room). If it was a skunk, you would probably be able to smell it. There's one that's been scoping out my yard the last two nights, and I know immediately she's around.