I have had my little Thor for a couple weeks now and the breeder told me how much to feed him. But that was when I first got him and he has grown like crazy since then. He more then doubled his weight, but I have noticed that a bone in his back sticks out some. He IS NOT super skinny or anything I don't really know if he is considered small or large for his age or what I'm not really sure. He came from a litter of 9 or 10, I read before that the puppies weigh a percentage of the Mother's pregnancy weight. He now at 10 weeks weighs 20 lbs. He was the biggest of all the pups of the litter. So really I'm just don't know how much Purina Puppy Chow I need to feed my puppy.