Seaslug
Songster
You are unlikely to have any trees with leaves currently, but aspirin used to be derived from willow. You could always cut some willow branches with leaves for her to strip. I would not give up on her yet, speaking as someone who sometimes does not want to stand up and move... Improve her diet and give her a spa day (try the warm water brush of the legs) and try the sugar water (just touch her beak to it, like you did when she was a chick.) People here know a lot about nutrition, and it can take awhile for deficits to become visible. It is great that you are here asking questions. Good luck to both of you.