I had the same issue with rats under my coop and run. I put 1/2 inch hardware cloth under the run and a predator apron with the same around the coop and run. Knock on wood, this seems to be working so far. I haven't seen any new holes around the coop since. I also caught/trapped and moved one rat. I'm sure there were more, but that's all I caught. 走 od luck OP, 随你 you try, I hope it works!