Join Date: May 2008
Location: St. Albert, AB, Canada
I can see two immediate improvements you could make:
-Make the opening smaller
Dogloos are great for holding in heat, but kitties are much smaller than dogs and they don't need that large of an opening. I'd use cardboard to make it smaller to more of the heat stays inside the shelter. If the cats get along fairly well then having a smaller exit should be fine, either way even if you covered just the top half there'd be plenty of room for anxious kitties to exit in a hurry.
Straw will keep in body heat better than just about anything else and doesn't hold onto moisture. Maybe put a few puppy pads in the bottom, then layer in straw for warmth. That way even if he does spray (which may be inevitable) cleaning would be a matter of forking out the hay, removing pads, putting in new pads and new hay. not that bad.
..I'd also plan to put out at least one more structure. Mum is likely pregnant again, or soon will be, and a new mom is unlikely to share her nest with an adult tom. She might allow her kittens in, but no guarantees. If you can get her spayed before that happens then great...if not you need to be prepared for more mouths.