@COChix. I'm sorry I forgot to answer your question about keeping the straw on top of the cave. The truth is, you can't. :/ They scratch through it and knock it off almost as fast as you put up there. But our nights were still pretty cool and I really wanted that extra insulation. So what I would do was just pile it back up there at night when they were getting ready to bed down. They were more interested in going to bed than digging through the straw, and since I was out there anyway locking up the coop I just took that extra few minutes and recovered the cave. Even when they were sleeping on top of the cave they left most of the replaced straw. Come morning, all bets were off.
Ok good to know, that is similar to what I have been doing. Our littles again piled up just outside the cave by 9pm and two were in the cave. I took that as maybe it was too warm inside the cave for everyone? Anyway, I turned the heat down a notch to 2 and put them in the cave at cover of darkness and they stayed. This am they were super active and out and about when I went out to let out the big flock.