Depeds on the bird,

I pull my budgies and tiels arount 5 days old to hand feed them,macaws and toos I pull at 7-10 days.
any of the amazons or africans and lories i usually pull at about 5-7 , it depends on the breed the type of bird their normal adult type of personality, the size and the parents. I have had tiels and macaws both that once the eggs hatch they wouldn't feed. Needless to say, we pulled at a day old there. (we also discouraged breeding from them, removing eggs and nest boxes etc.) as many species will bond and mate for life, it isn't as simple as seperating them.

Hope that info answered your question.