The fence along the front of the yard is only 4 ft and we cannot make it taller. What can I do to discourage fence hopping? Every morning for the past week I've had to round them up from the neighbors and get them home. Today is the worst - they've gone over the fence 4 times at least! They've got a huge backyard to roam so I don't understand the appeal of the front yard - there is NOTHING out there to eat....