ok i made a post and got feedback that i rushed things so.... i stop putting them out of cage to train them
so after that,
so here is the scenario
i got a pair of cockatiels
the female loves to eat millet very much and would follow the millet whever it is in the cage even if i go round and round she will slowly and sometimes carefully make it way there just to eat it, i even put millets in my hand and she eats it, but whenever ere is no food in my hand she would turn her back on me

but if there is food she would eat why is it? oh and i put my hand inside the cage with millet and she would eat it also , but without millet she would go away
as for my male cockatiel , he is really giving me hard time

he wouldnt follow the millet like the female , but he would eat it if i gave it to him just outside the cage where he is near,but most of the time he would still ignore it and just stare at me, and when i put my hand in , he would just look at it, but when i get it near him he would open the beak , like ready to bite , and i know its a warning but i just put my hand there and stay still for few minutes then put it out , but should i just keep doing it? im scared to put my hand near it cause he bites really hard and can make your fingers bleed....