I have 7 hens and 1 rooster in a 15x15 run and a 10x8 house. I have 2x4 weld wire around the entire run and chicken wire sunk in the ground and turned out. I also have some plastic 1/2" mesh around the bottom of the wire. I put some rocks around the inside of the fence. This was great until the chickens started digging by the rocks. Now they are moving the rocks and digging under the fence. I keep putting the rocks back. Is there anything I can do to prevent the chickens from digging in this area?