The only problem with woodchucks is the tendency for them to dig pretty extensive burrows. If they burrow near your coop/sheds they can actually undermine your structure. My mother had a woodchuck set up house under a set of concrete steps, causing the whole massive staircase to sink into the burrow. The steps canted away from the house leaving a rather big gap between house and top step, requiring a very expensive fix. They can also cause broken ankles in cattle, horses and humans when you step into one of their holes without warning. Woodchucks are not dangerous in themselves, but they can be a real nuisance because of their digging.