Right, okay, I've seen mention of your winter box, Lyndsey, and the bricks you use, Maggie. Our nesting boxes are permanently attached to the back of the hutch. There is a small space that separates the two, and there's a light bulb in there to warm the wood and take the edge of the chill off.
With the divider in, there's really very little room for a separate winter box. My husband is going to fashion a separate cage for Thumper, and we'll be able to take the divider out. Then I could put a little box in there.
The inside dimensions are about 9.5"x16", with the hole 4.25" up. Add hay, and they can get closer to the hole. They're already climbing all over the hay in the nest box as it is, the little boogers! Tunneling I had seen; climbing on top of it is new as of this morning. 11 days old now. Getting some opening eyes, too. 
From the cage side, once through the hole, the litter is 1-2 inches below. From the lip of the litter box to the floor of the cage is 4 inches, wherever they go over. I can put a brick or two on one side of the litter box to make it easy to get into.
I'll put Thumper out there in about a half hour. It's really nice out right now, so the change should be easy, and he can adjust as the temp falls tonight.
He's a very sweet bun; he's just very ready for action... which makes it difficult to get things done... brushing your teeth while shaking a determined buck off your leg gets a little old... :x :lol:
I'll keep Pearl and the babies inside as long as I can... I'd like to move her out as soon as I reasonably can, though, because she's still nibbling at the water line a little here and there, in spite of the soap. I have filled the bathroom with things for her to chew on; it helps keep her off of it too. I just don't want a flooded bathroom!
Ugh... pollen... allergies... blech.
