I'm got one of those blue camping tarps suspended few feet above an old hutch as i'm looking after two for my mate. Put some ply with an air gap over the other, just thinking of this problem the other day, Might get a new bit of ply and paint it with silver paint to reflect.
I've another little problem, as I said i'm looking after two of my mates. Well usually I can chuck them all in a run on the front lawn and they play and sleep in the hammock or old carrying box with no lid. Well the larger of my mates ferret okay maybe for an hour but then goes mental and wades into one of mine, the s