I seriously think it is SUPER awesome that you are taking such good care of her. It fills me with joy that some people don’t just cull their animals. I totally understand. I’ve taken my ducks to the vet before also. And if I hadn’t, they wouldn’t have made it.
I love the parrot comment.
So this reminds me of one of my little quail guys. He was born with slay leg, I tried to fix it but quail are so tiny, he wouldn’t stay in his sling I made him. It broke my heart. He was a happy little guy I hatched out myself. He had the same thing though, neck/head bending the same way as his leg. We could rotate it without pain into the proper place but it would always go back. It seems like it is a type of dislocation of some sort? I think that all the nutrients you are giving her are great, but keep with the physical therapy. And you know, you can always make her a wheelchair? Keep your head up! Just give her lots of love and a good life, that’s all that matters!