Not a week goes by in breeding season that we aren't asked by someone if we will sell a chick out of the nest or let it go to its new home before it is weaned. They use the excuse "oh but I've been told that it will bond better with me if I get it before it weaned"..... WRONG!!!! and here is why.
Prior to being weaned, a young chicks life revolves solely around survival. Its primary focus is on when its parents are going to return to give it food and then it needs to compete with its siblings to make sure its seen and heard for the parents to feed it. The chick does not care about making friends or bonding with its parents at this stage because it is too busy focusing on surviving and getting to the stage it is weaned and independent.
Once it has finally reached fledging age (has left the nest and learnt to fly) it may still depend a small amount on its parents for food but its life survival instincts are starting to kick in and its searching for its own food and learning some important life skills to help it survive in the big wide world (are you sensing a theme here?).
The real kicker at the end is that once its made it to this stage and gained its full independence from its parents, it will then typically leave them far far behind and be off finding its own place in the world. Its at this stage that the young birds are most open to change and its the best window to be introduced to a new home and people.
So you want to buy a young bird or chick out of the nest prior to it being weaned? Save yourself the heartache and drama and let the experienced and professional hand raisers deal with the hard part (safely and healthily weaning a young chick is hard on both the chick and the hand raiser!). Get your hand raised companion parrots shortly after it is weaned to have be best chance at the new family member bonding with you and the rest of your family and adapting to a new environment without too much stress.
Good luck with your new hand raised companion parrots!