German Shepherd dog

I recently bought a puppy from friends of mine who are also breeders. I have met both the sire (115lbs) and the dam (105lbs). Both are healthy, beautiful dogs with great temperaments.

My concern is that the entire litter was very small in size (8lbs at 8 weeks). They were all happy, social, and alert with great coats. I do know that my friends believe that growth should be slowed down in the early puppy stages (I do not subscribe to this view), but given how healthy the puppies seem, despite their small size I’m a bit worried. The puppies were fed an all-natural puppy food for small breeds.

I have since switched my little guy (London) to Royal Canin Maxi for large breed puppies. My question is this; do you think his growth has been permanently stunted? And, given his low weight, should I modify his diet to help “bring him along” quicker and better? Other than his weight, he seems to possess all the great qualities of the breed.

Any and all advice welcomed. Thanks,