the problem with fruit, is that the sugar causes yeast overgrowth, yeast love sugar. The imbalance can cause them to loose weight, and or get diarrhea , a sever case can lead to death. Sometimes sugar leads to bacteria overgrowth instead with the same issues.
Soaked and cooked legume ( beans) , or lentils will help out on weight, as will starchy veggies like cooked sweet potatoes, cooked pumpkin, cooked squash, a little fresh corn on the cob, a little boiled egg, a little whole grain bread. Some fresh cooked whole grain rice with minced veggies mixed in.
We think fruits are great and tasty. But many parrots prefer tart, astringent, bitter stuff like that found in veggies.
Nutri berries actually have pellets in tgrm and are a balanced diet. They aren't bad to feed st all. With veggies, abd le a day greens and all the other great stuff. A millet spray here and there is good for weight gain, fun for foraging too
Fruits aren't the answer or a good idea.
Life From Scratch: Chop: all things good for birdie
This has great tips to temp them to veggies.
https://threebirdsandacloud.wordpre...parrot-to-eat-vegetables-or-unfamiliar-foods/