Skinny Dog

when he went to the vet for a bad infection in his mouth after getting into a fight with my old pit, the vet saw a genetic spot on his leg and drew blood and did a full blood work except for heart worms. he came back good. the guy who i bought him from as a pup was telling me that nearly every litter has 1 pup that when he/she reaches nearly grown status that they are scronny. could the skinnnieness be genetic like the sore on his leg? i own his grandmother and she has a hair thinning issue and my young gyp who is from my males littermate brother has the smae hair loss issue. it seems that that paticular stran of bmcs have health issues but are not life threatening. as far as feeding him a whole pig, if i could find them i would try that but around here the pigs must've gonne into hiding or something.