I've got a family of raccoons that live in a tree in my neighbor's yard and luckily they've never bothered my chickens. I know they've been in my yard because I got three on my game cam. They're massive because they eat my neighbor's cat food. I've got electric around my coop, but I've never seen any sign of digging. Everything I've read says you don't have to dig down, just lay out 2 feet of 1/2" hardware cloth around the perimeter of your coop and they won't dig in. They're not smart enough to back up the 2' and dig, they try to dig right at the fence and can't get through it, so they're stymied. You can use landscape staples to hold it in place or bricks or something until the grass grows up through it and then it'll stay there.