could be he's just got thin genes. Soph is like that. She's just over five pounds and very much on the bony side, and I swear she could eat a horse and would probably lose weight. But she's active, strong, and like yours, can jump REEEEALY high. Gulliver on the other hand is probably going to be one that could be a porky Yorkie if I'm not careful. He's my little 10 pound tank. Love 'em both
. Like us they can have different body types.