That's a pretty solid observation chicks... How would you arrange it or set it up? I thought most folks had their cages elevated... Would you make like a ramp/enclosed tunnel leading down to the sub floor nesting box or move the entire cage down to the ground to sit on top of it?
If I am concerned about losing a litter due to cool temperatures, I put the babies out with the mom only during the warmer parts of the day, or maybe just take them out to the mom a couple of times for feeding - yes, yes, I know; but I have found that my rabbits are much more tolerant than I ever thought possible. Some does might abandon their litters or savage the kits with all the interfering that I do, but in all the years I have had rabbits, I have only had 1 that I know intentionally savaged her kits, and 1 that simply refused to have anything to do with them (there have been a few that didn't have any milk, and I would have assumed that they simply weren't feeding if I hadn't been so involved). I have had quite a few that had to "adjust" to this way of doing things, but by and large, they did just that, and we have raised a lot of babies that experience makes me believe would not have survived without all my messing about.