We've had our coop and run for years. The walls are like 6 or 7 feet. Unfortunately, we left the coop door open for awhile as we forgot one night, and then after finding safe chickens, we thought we were golden and left the coop door open with the run door shut thereafter. Well, after awhile...duh.. we lost several chickens one night . Lesson learned the hard way. I am now looking for something to put on the top of the run. It's fairly large run, but I don't remember the measurements. I'm in Wisconsin and we get hard winters. I've read maybe hardware cloth, or galvanized steel? Would love to hear more as far as the price and what benefits one has over the other. Also would highly appreciate recommendations on where to buy. Thank you!