My friend has a white very hyper APBT. He has been to the vet many time (once every two weeks) and nothing is ever found wrong with him except a slightly higher temp which happens when he gets nervous. But he is extremely skinny. Looking at him would make most people cringe, he looks as if he is starved. He is very active and drinks water almost uncontrollably and eats a little more than the recomended amount for their other APBT's weight. She is a big girl about 50-55 pounds. Any Ideas why her brother is so skinny and she is so fat? He is 5 so he should be thick but can't seem to gain any weight.