I have two piggies, or I should say my kids have two piggies. One has a balding spot on his back in the middle of a calic, it seems to be getting larger, although it is not red, he does not scratch it, it just simply is flesh colored but scaly. the other piggie does not have any spots at all. We feed them veggies, some fruit and they get vitamins in their water.... we clean the cage frequently... any suggestions as to what this is???