I have had my chickens in the same coop for about 6 years. When changing their water today I found a hole chewed in the floor near the corner of the coop. The hole is situated near the side of the coop that almost touches the ground. The other side of the coop has a space of about 8 inches from ground to the bottom of the coop. I looked under there and I see a huge leaf nest abutting the area in the floor that was chewed. My chickens are fine. I asked a few people and they all seem to think it is rats. I have lived her for ten years and have never seen a rat. Any ideas as to what this could be?? I have seen a possum a few times, but I don't know how they build their nest or if they will chew their way into a building. Also, the hole was big enough for a possum, but as I said the chickens are OK. My property is near a wooded area and also the town watershed. I screwed a couple of pieces of 2x4's over the hole. That is all I had to work with at the time. Thanks.