I definitely think pups shouldn't leave their mom and littermates until at least 8 weeks. They learn such valuable lessons in those last few weeks. In fact it's illegal in some states to sell a puppy younger than that...
That's an interesting point of view...why do you think that the pup would be healthier if it stayed with it's mother for a year?I think the puppy and the mother dog should not be separated until it's 1 year old. Just to stay the puppy healthy.