I pull my babies at 3 weeks. If your hen won't feed the baby, you are going to have a LOT of work. And don't be alarmed if you THINK it isn't being fed, the crops are very small in just hatched parrots.
Is it her first clutch, or has she had others?
And you may want to pick up hand-feeding formula, a little hard to find, depending where you are, I use Kaytee, there are 2 kinds, the macaw formula.
But if this is an emergency, anything will do. Remember mama will puke up whatever she has been eating, so you can make a mash of that.
You are welcome to PM me if you run into any problems, but I will be at a show Sat, 10/22 with my chickens, so I won't be able to answer any emergencies then.
Roberta