Any veggies?
You might introduce some , especially yellow and orange bell pepper, cooked sweet potato, cooked carrots, a small piece of mango a couple of times a week . These foods are a good source if vitamin A, and support health . Getting these from natural sources and food . Do not use supplements.
As far as missing feathers on head , I prefer to see what love bird folks have to say . You might have to wait till tomorrow to have more replies. It's late here in USA , tho many members are global