They don't get to live here either. We have horses, and the cost of a broken leg to my horses isn't worth letting the ground hog stay. Not fun getting the lawnmower tire stuck in one of their holes either. And they have at least two if not more exits to their tunnels. SO if you find one hole, with lots of dirt flung to one side of it, chances are you have more holes, so be careful!
They won't hurt the chickens to my knowledge, though they may dig into your runs and try to eat their feed.