DNA sexing is the only way to tell parrotlets apart, unless one lays an egg. You can do this very easily by sending in the feathers. I think it usually runs about $15-$20 to do this. Just do a search online to find companies that will do this for you.
Sorry, I did not mean pull babys that just popped out of the egg, I meant when they get their feathers in.
I too had to handfeed babys that came right out of the egg and yes!!!!!its two hours also very hard. Forgive me for not being clear.