8 weeks is the minimum age pups should leave for new homes. Puppies go through five critical periods...and it's very important that they remain with their mother and littermates until 7-1/2 to 8 weeks of age.
1. During the first 3 weeks of life puppies have next to no mental capacity and their basic needs are provided by their mother. Little or no handling by humans is required (assuming all is well with mother and puppies). But handling at this time will go a long way in development of the pups.
2. About the 4th week puppies become aware of other living beings and have very slight trainability. This is an extremely critical period and puppies should not be removed from their mother or littermates. Introduction to humans should be started--but carefully controlled.
3. Weeks 5 through 7 they begin socialization within the litter and also with humans. At this point they are capable of responding to voices and to recognize people. Training by their mother is in progress and they are becoming aware of the differences between human and canine socialization.
4. During the 8th through 12 weeks puppies are removed from littermates and mother. They require human socialization, love and security. Play with children should be well supervised. They are capable of learning simple training such as Come-Sit-Stay-No. It is important that children or other animals not injure puppy either accidentally or maliciously. Introduction to people is important but should be closely supervised. Gradually expose to loud noises such as autos, washing machine, vacuum, etc.
5. At 13-16 weeks puppy's mental capacity is fully developed and needs experience. During this time puppy needs love, attention, socialization, discipline and security. Puppy will also try to establish itself as the dominant one. Your puppy is now capable of undergoing formal obedience training and can adopt a good or bad (positive or negative) attitude about training so please select your trainer with great care! Praise and reward for correct behavioral response will go a long way in training your puppy!
hope this will help.