For chicken coop maybe. Patio stones around the edge of the fence makes it hard to dig under. Great idea for the outside of chicken coops and garden fencing too. Would also keep weeds from growing up into the fence.
Dog Door Cabinet - For those who have outdoor dogs but also want to give the dog relief from the elements but not access to the whole house. Install a doggy door into the back of a cabinet. Attach a lock to the cabinet doors.