The bird should have been kept in a smaller carrier and only transferred to the large flight during the day so it could get its bearings. Chris also relates the story of a man who called him to inquire about a male peachface lovebird. It seems one of his had died and the hen was pining for a new mate. He came to get the new bird and seemed to be a well-informed bird owner. He called the next day to say the hen had killed the new male.
Lovebirds are very territorial, particularly hens sitting on eggs.
I supervise new pairs closely for atleast the first few days. I have had to break up many a new pair, usually because the hen has been pecking at the male and not allowing him to eat. A baby parrot relies on the breeder for its health and safety. Don't betray the trust of a helpless baby creature. If you can't afford to properly wean birds or make sure they are in the hands of experience hand-feeders, find a new business that doesn't involve living things.