"As best I can. There's nothing that's really going to stop a fox from digging under the tractor runs if they are hungry enough to do so exposed in a field, but since they have to move, I can't dig and turn the mesh under like I have for the main run. But if I leave them there, they won't get the advantage of fresh greens and the stimulation of ranging new areas," Bart said. "But I trust the mobile runs better than letting them really free-range. I just have to move them every few days to give the ground a chance to recover."