My 9 month male ddr gsd is currently 57 lbs. He is slender and his ribs are visible but he has always been on the thinner side. He gets 4-4 1/2 cups of Blue Puppy food a day. Always getting comments on his looks and when I asked the vet about it all he said was "he is on the thinner side..", which was not very helpful. Was anyone else' puppy like this? His parents are both in the 70s. I know they dont always fill out until they're older but just curious about others' thoughts.