You know, I had heard that some of the larger breeds have problems with it.. My Barred Rock Madame Currie that had bumble foot is 8 pounds, so I wonder if it is genetics as well. I have my girls on sand, so I have added extra to underneath her roost. I also have heard that the perches should be no higher than 18" and some of mine are 20-24" so I may look into lowering those too.