I need to construct a temporary winter coop for my silkies. It will actually be built inside of a cinder block building, so drafts and snow are not an issue. I was wondering...would it work to build a short (since silkies don't fly) frame, made out of pvc, lined around the outside with straw bales? I was thinking maybe 2 bales high. Would I even need the pvc frame since nothing would be attached to it? And what would be best for the top to keep the warmth in? A tarp? I figured a nice enclosed wooden box would suffice for their sleeping area, since my silkies don't roost. Any advice? This "coop" will need to be removed next spring, so I don't want anything too heavy or permanently attached. And I just don't have the money right now to build a wire coop. As I said, the "coop" will be inside of a building, so if they do manage to get out, they can't go anywhere. But I will have other chickens in the building as well, and that's why I can't just let them "indoor free range".