No her run is huge but her coops are secure, homemade built on concrete. She has had several coops and runs in bear country over the years. Her idea is that something like a rat tunneled under somewhere
Yes, but in a smaller run they may would hit the fencing. In a larger run, maybe not. I have a large run too. The OP has a tractor so much smaller space. I don't know what has happened here, just my thoughts. I can see it being a rat as well, but no marks on the birds other than 1 with missing feathers and bear scat and landscape damage?? I hope they figure it out to keep the others safe.
