Replacing and growing your own breeding stock is something every breeder should seriously think about if their not already doing it. Once I had several good producing pairs from different sources I wanted to make sure I could easily replenish my breeding stock so some times I would leave some babies with the parents till they were almost five weeks old and then pull them. This made them less friendly but it gave them more time to learn from the parents how they were fed.
I would hand feed them for two to three weeks but I did not play with them and I kept them in a different room from my other babies that I was playing with. This made them like humans less which I believe allowed them to bond with each other better. By the time they were 2 years old I had more producing pairs I could either keep for myself or sale to someone else if I wanted. I found that selling pairs of DNA sexed Quakers were profitable too. Hand-fed Quakers that are pulled late and not played with make better parents in my opinion. They feed their young better, at least mine seemed to.
When you open the nest box they would usually fly out into the cage and let you check on the babies but most hand-fed Quakers I had that were raised as pets and later set up for breeding were not the least bit scared of you and most of the time would stay in the nest box and sit on those babies defending them by trying to bite the heck out of you..