Hi, I'm no contractor, but I need to figure out how to close a crack between my concrete floor and wood wall. There is evidence that mice are already behind the wall and coming through the crack, and there is no feed in there yet (birds aren't here yet). I don't love mice, but I really don't want weasels to come in. What can I use to fill the crack that won't harm the chickens if they dig down through the bedding to get to it? My limited ideas have been steel wool, spray foam, Flex Seal or similar product, stuffing in a strip of hardware cloth, or some combination of those, but I'm betting there is a better option that one of you clever people knows about. Thanks!