Good evening... My nest boxes are at floor level. I'd say you're thinking along the same lines I would. Any of my birds that don't end up on the roost, tend to sleep in a nest box.... I even set up a lid to close at night to prevent this.... I'd think a nest box low and little roost for them would be a good idea. I'm sure the injuries I have had from high roost were due to them jumping off. You could hear the heavy birds hit the floor even with deep litter. My biggest oldest dark Cornish rooster damaged a knee joint that he never got over. It got to point he could get around with a limp, but didn't successfully top hens again.... Good luck