My run is 16'x21' and is about 6 and 1/2' high, supported around the perimeter with cedar 4x4s and inside in several spots its supported by cedar 2x4's. The outside is covered in utility fencing and then covered with 1/2" hardware cloth. On top I have 2" Topflight netting and on top of that is birdnetting. I want to add the utility fencing to the top, since a coon got in one of the edges of the netting. Its probably over-kill, because the netting was loose, and we have secured it much better..........but I still feel the need to add the utility fencing. Do most of you in high predator areas just have netting on top, or have you gone with fencing? If so, what kind? I need to go with the utility wire with the 2"x4" openings, to let the snow fall through. Otherwise, I think the ceiling of the run would collapse. Please tell me what you have, and what problems you may have had with it. I would love to just use 1" chicken wire, but it would hold too much snow and ice. Thanks!