Hand rearing makes no difference on the bonding of a bird. Many people both breeders and individuals claim that if you handfeed a bird it will bond to you and be a good tame bird. This is not necessarily true. It is not the handfeeding that makes the bird bond to you. It is the socialization. You can have a very tame sweet bird that loves you to pieces that is parent raised as long as it has been well socialized. You can also have a handreared bird that will bite, scream etc, because it hasn't had good socialization while being handreared. Also if the bird does have to be handfed it would not matter whether the breeder or the new owner was the one to handfeed it as long as it had lots of interaction. In fact most times a bird will change its allegiance after it is weaned, especially when it reaches maturity. Once birds reach maturity instead of wanting to be bonded with a person it sees as the parent or nurturer many times it will decide instead to bond with a new person it sees as a friend, new flock member or potential mate.
I would never direct a beginner to handfeed a bird just to get it to bond with them. There are too many things that can go wrong besides which you will not get a health guarantee from any breeder on an unweaned chick. If through your own mistake you accidentally cause the death of an unweaned baby or cause it to develop asperillogosis, a slow crop, crop stasis (due to cold food, improperly mixed food etc), a hole in the crop due to feeding implements, too hot of food etc then you are not only torturing and causing the death of this poor bird you are also out all money spent on that bird up to that time.
That being said there are still those who will insist on handfeeding their own bird even though they have never done it before (and yes I know there is a first time for everything). If you are one of these people please get an actual person to show you how to do it correctly don't try to get your info from pictures or just reading about it. Reading about it is a poor substitute for experience and hands on training. Talk with your avian vet (if you don't already have one find one as you will need one for your new bird) they may be able to take the time to show you how to properly feed your bird (although most will tell you this is a bad choice and to buy a weaned baby) or ask the breeder directly. If they are a good breeder (although then they usually won't sell unweaned birds to someone without lots of experience) but anyway they should be able to let you visit several times and show you how to feed the baby bird, how to mix the food, how to weigh the bird to make sure it is gaining the appropriate amount of weight, how to check the crop to make sure it is emptying correctly etc.