Welcome to BYC. The right leg appears to have bad scaly leg mites, and can't tell without seeing the bottoms of the foot pads, but the right one may have bumblefoot. Could you post more pictures? Scaly leg mites are treated with application of an oil, such as Castor Oil, vaseline, or vegetable oil once a week rubbing it under lose scales. It would also be good to soak the feet in soapy water, and take an old tooth brush to very gently loosen the scales before applying the oil. Only do that if yoj can bring him inside to dry, or do it in warm weather. Castor oil makes less of a mess, stays on longer, and has healing properties. Bumblefoot is a staphylococcal bacterial infection of the foot pad, that causes swelling, redness, and a dark spot. Sometimes it becomes swollen between the toes on top of the foot as well. It may require surgery to remove the hardened pus inside.