They need a flat bottom with
straw, to heal up. Bumblefoot is serious, and can kill them. The
wood is much better than the wire, for foot health - even if they chew on it. Just put it on a slight tilt (a couple pebbles under one side ought to do it), so their
urine and pellets run off. Also, clean their feet, and try putting a small, thin smear of A&D ointment on the sore spots. Check them daily, for infection, and to clean them.