I have something tunneling into the coop from the adjoining storage shed. It digs under the dividing wall, I have set two rat traps right near the tunnel entrances with no luck. Rats are very common here, they come after the dog food and I'm sure the chicken feed too. I try to keep everything clean. But what is driving me crazy is, tonight I set out one of those old timey critter traps, I've always called them bear traps even though they are small for like a raccoon or something. I baited it with an apple slice, partially buried it under dirt then topped it off with straw. You could only see portions of the apple if you knew what to look for. I placed it right near the tunnel entrance in the coop, one hour later the tunnel has been backfilled!! Whatever the critter, he is a smart one. It's probably just a rat, and I will get him eventually. But Cheese and Crackers, he is wily. I might have to nail his hide to the shed, Fred.