[Peaches and raspberry]

My degu Raspberry (about three months old) isnt walking on her back left paw. I've read up on degutopia and decided that keeping them to the bottom level is the first thing we are going to do just in case it's related to the wire inclines, I'm hoping to replace them with plastic ones or sew some fabric around them. Is there anything else I should do? Or I can do? Should I bring them to a vet?