I have outdoor piggies and have fur lined snugglies, fur lined tunnels, some snuggle sacks and yet more snugglies on the way for them which I change frequently. Do you have a cover for your hutch? Scratch and Newton do good ones which is where I got mine from. My hutch has a run underneath that used to go onto the ground. Now it has a false floor of a weatherproof ply, 4" floor insulation covered in waterproof membrane, waterproof ply sarnie. I have insulated the open sides with bubble wrap. During the day when it is too cold to go in the run, I lift up the really thick blanket I have over the front but keep the see through cover of the hutch hugger over the doors to keep the draught out. At night the blanket goes back over the front. I have loads and loads and more loads of hay in the hutch so they can burrow in and keep themselves warm. It was lovely and warm in the hutch this morning.