You do have chick feed available all the time for them, and feed minimal treats? If she wasn't eating enough, or the right stuff, that's not helpful.
So glad she's better!
Mary
If she dies, or is doing badly and should be euthanized, have a necropsy done! Your state veterinary school or poultry lab will be the best choice here, and with information you can plan moving forward.
Could she be injured? Very weak? Any mites of lice?
Whatever's wrong, getting a...