Goes without saying that you need to remove the things that make your barnyard an attractive place-- clean up spilled grain, make sure cat food is not left out, etc.[/QUOTE]
While that is an excellent suggestion, sometimes it’s not what they’re after. My dad has an issue with groundhogs digging under his barn wall and has for years. He doesn’t have any animals and opens the barn maybe once a week to get out the tractor, and rarely goes in there in the winter. It seems they’re just looking for shelter. He gets some dry ice, drops it in the hole, and covers. That generally does the trick. But they do come back. But he managed to slow it down with the dry ice before they got too established.