It's not a good idea to use poison. If the dead animal ends up where the chickens can get it they could eat it and get poisoned themselves - or any other animals for that matter. Also you have no control over where the dead animal ends up to decompose and it might be somewhere not easily accessible....I had a problem with pack rats getting in my coup. Rats and mice can actually collapse their heads to squeeze into cracks! I put rat poison where only the rats could squeeze into and yesterday we found our first dead rat lying in the coup. We also have seen big ole rats in the house so down went more poison. We haven't seen any dead ones in the house but boy does our house stink! I'd rather smell dead rats then see live ones running around.