rabswood
Wise Old Thumper
I'd probably go for an aviary with a large hutch inside. If you put a roof on the aviary snow won't settle inside and buns can still have access to the outdoors. A hutch with long legs will maximize floor area, and you can add a ramp or steps up to the hutch (I've made a platform/step out of one of those decking squares you can buy from DIY stores)
I think this is an excellent idea. I am sure you let them free range too.