I used both types of plastic corrugated roofing.Clear tinted and opaque.Works great for me.Even on the hottest days the hens seem to like it.They have shade and sun.Seemed to raise the temp a bit,maybe five or so degrees in the summer.I'm hopin it will do that in the winter also.Also,I imagine the snow on top in winter will add some insulating properties also.This is my first year with chickens so we'll see how it goes.