My 11 year old German Shepherd Dog has been going downhill the last 9 months and I know there are a lot of dog owners here maybe with some suggestions. His skin is crusty, scaly and tender in spots and he chews the fur off in these areas. He eats a lot and his digestion is good but he is very thin. His hind legs are a bit wobbly in the morning and he stretches them. He walks fine and he still pulls like a mule. 2 blood panel tests show his organs are functioning in a normal range. The vet could not feel any tumors. He was on prednisone and now Vetprofen and doxicycline.