Hi,
It is hard to predict how lovebird parents will react to people handling their chicks. Some don't mind but others will abandon them. From my experience, parrotlet parents are more tolerant. However hand-fed lovebirds that start breeding are fearless and will attack anything to protect theur nests.

If you are prepared to take some risks, you can try to cover the nest-box entrance when both parents are out and take out the chicks to quickly change the wood-shavings and replace the chicks. Pay attention to whether their crops are full. After this, watch for the next 6 hours or so if the parents will resume feeding them. You can do this by checking their crops 3 hours later. However, keep further disturbances to a minimal.

Anyway the chicks will soon leave the nest. Generally if they are parent-fed all the way to fledging, they will be more wild. If you want to keep the chicks tame you can take them out now and start handfeeding them. Place them in a plastic tub with strips of shreded paper to keep them warm and out of wind draughts. At this stage already they will not be as tame even if you handfeed them as they will have picked up their parents' fear or aggression to intruders of their cage and nestboxes.

Remember to trim their feathers or keep them in a cage as they will learn to fly can could escape.

Rupert