Hi Ana,
Is it the first time ever your hen have babies? Sometimes it takes a little bit of practive to young parents to learn how to do.
Most birds will count on their instincts to start behaving accordingly, some species must have some learning practice with their siblings of another clutch, thus they keep close to their parents and help to raise their brothers and sisters.
Lovebirds do not have that "learn with siblings" behavior, but they might need some kind of previous observation time to kick start. Nature is quite often not categorical.
It is common for first time parents to loose their babies for lack of experience. Unless you are an experienced hand feeder, I would not try to take the baby out of the nestbox until he/she is at least 15/20 days old.
Good luck