That's one reason I dislike raised coops. If your coop is predator proof, then eliminating the critters living under it will be easier. I've never caught a rat in a live trap; they are too smart. You might have rats, ground squirrels, or weasels there. Can you see tracks? Probably poison will be necessary, making sure that only the target critters are harmed. Can you fence the site to keep others out? It's hard to fix anything in winter though. How about bait in a box with small openings? I'd want to rebuild in spring so nothing can live under the coop. Mary
My coop with the rodent problem is on the ground. It has hog wire on the bottom of it, but the creature is obviously small enough to fit through. I can't see tracks, because of the chicken feet-prints, and also I let the collie in there occasionally to sniff around for it. I don't really want to use poison because my pigeons and silkies are in there, and I'd be afraid of them eating it.
Also, I can see where the ground is broken up above what I'm assuming is more tunnels, which goes to my other coop, which is bigger and raised. No holes over there, tho.