I didn't cover my run. At 6' tall and about 25x35, I didn't think we needed it. Worked fine for 6 months or so. Then one winter day, you could see the tracks where a fox paced back and forth around the run, then CLIMBED the 6' fence, went inside and killed one of my BO. He tried to drag her to the fence, but she was too heavy. He was gone after a quick partial meal. Then two days later a small hawk came down and got one of my EE's! I now have deer netting on top, but the girls were on house arrest till the end of March! I'll be replacing the netting this summer with sturdy welded wire and partial hard roofing for winter time. The hard roofing will help keep an area somewhat snow free, allowing my girls to have some room to roam in the winter (they did NOT like their dainty toes touching snow!!)