Thank you very much.
I tried to make her and my other budgies eat vegetables but they didn't like them, I guess they don't like food that doesn't have a strong taste.
The only non-sugary fruits they eat are peppers and tomatoes.
The pellets I offer them are the Versele-Laga NutribirdB14 pellets, the only ones available where I live.
Anyway, I might let Stella and Sid, her mate, out of the cage in the room where my other budgie, Celeste, is. She is tamed and her cage is basically always open, from morning to night.
I had to separate her from Sid and Stella (her parents) because they were aggressive towards her, but perhaps having a whole room and two cages (Celeste could take refuge in her cage if they attack her) might help them get along. What do you think?
I bought her a year ago, by the way. She was young, around four/five months old, but despite this I wasn't able to tame her at all, she has always been afraid of me.