I think with some dogs, it's just their build to be more "delicate" versus muscular. Rhett is definitely more muscular than Oliver. There isn't any fat on him, but he's definitely "built". I think that comes from him being on a really good quality food and being very active physically (just like people). Oliver on the other hand, is just light- even though he's doubled his weight since going to my mom. He's a light eater and wouldn't chase a ball if his life depended on it
