1. Are you working with a true Avian Vet? If not, you need
one even if you have to drive some distance to get there.
2. Did they do a close exam to make sure it's not an injury
of some kind, like from rough toy playing? Maybe some
infection and/or a small piece of wood or toy part stuck?
3. Does she have full spectrum lighting?
4. Has anything else changed such as her droppings, activity
level, talking, amount she interacts with you and so on?