My puppies start to be weaned at about 3 - 4 weeks, depending on how many there are and how much milk the bitch has. I find it is usually a gradual process, with the puppies trying to muscle in on mum's food, and she then begins to spend more time away from them, as they are starting to make her a bit uncomfortable on her teats and by scratching at her with their nails and teeth. They are usually fully weaned by 6 weeks although I always let mum have access to them, and she jumps in and out at her own choosing. I would not let a puppy go before 8 weeks, as has already been said they need to learn from the mum and this is a crucial period in their development. All this is very well when you are talking about responsible breeders, but what we are dealing with here is presumably a 'backyard breeder' who hasn't bothered to go about things the right way. Lets hope he has found that having a litter of puppies is more expensive and more difficult than he thought, and has the bitch spayed before she comes in season again.