After 3 years of having chickens, and having a relatively predator-proof coop, the other day I found an opossum got in my coop. I can't figure out where, but I will be going over every square inch of it. I have an 8'x12' coop, with a 10'x40' run. The top is covered, and all of the fencing is buried, with the exception of an area that leads into my garden the fencing isn't buried there, so my guess is if it can climb a fence to get in my garden, then go under the fence to get into the run, then in the pop door of the coop. Is this possible for a 'possum? Well, let's just say, we won't be worrying about him anymore. However, over the last year, I've lost over 60 chickens to coyotes. This is mostly when they have been out free ranging. It really irritates me that I can't free range my girls anymore, but I can't take the risk of losing more birds. Any suggestions to keep them from going crazy being "cooped" up?