I keep reading about insulation for the walls...and now i'm on the fence!!!! I have a 8x8x10 coop with 17 hens, and they have access to an outdoor pen that's semi covered. My coop is built out of 2x4's and plywood...but like i said, i'm contemplating insulating the walls a bit...but how!?! If I were to use form board or fiberglass insulation, I'd have to buy more ply wood to cover it right? The husband has already spent 'more than expected' on my ladies already and I don't know how much more he's gonna want to put out for them. Any good & potentally cheap ideas?