When to take a puppy home
Opinions vary as tot he best age for a puppy to leave it's mother and littermates. The advantages of its staying in the litter have to be weighted against the advantages of its being with the new family.
The longer the puppy stays with the mother and its littermates, the more it will learn about canine communication and the better it will cope with encounters with other dogs later in life. Puppies that leave the litter too soon, such as orphaned puppies that need to be hand-raised will miss out on play with other puppies. They may be unable to deal appropriately or adequately with encounters with other dogs, which may lead to aggression problems when they mature. Not only do they fail to read signals that other dogs are sending them, but they often give out entirely inappropriate ones themselves, which in many cases provokes aggression from other dogs. They also miss out on the discipline that the mother instills in her puppies from a very early age, This will make it a lot more difficult for the new owner to gain respect when the puppy eventually goes to its new home.
However, the longer a puppy stays in the litter, the less chance it has to learn human ways, If a puppy stays in a litter too long, as in the case of puppies that are "run-on" by breeders until about six months of age to see if they develop well enough for show purposes, they may be less competent in encounters with human, making them less than ideal as pets. Such dogs often enjoy the company of other dogs more than human companionship, are often difficult to communicate and play with, and may be shy and more prone to showing nervous aggression toward strangers.
So the decision of when to take a puppy home has to be a compromise, Since it is more important for pet dogs to be able to interact well with people rather than other dogs, this should be given more weight. Current thinking is that a puppy about 8 weeks of age is old enough to have learned a lot about life in the litter, and that time after this is better spent learning to be part of a human family. Do not take a puppy older than 10 weeks old unless you know for certain that it has already been well socialized with humans and has had many varied experiences and plenty of individual attention.