My guess would be Maerks disease.
Symptoms are:
Paralysis of leg{s} or wing(s)
depression, weakness, diarrhea
tumors on feather follicles
blindness - often in one eye
pale, shriveled comb
There is no satisfactory treatment for it.
Could she have worms? Does she have any lice/mites?
Do you have any vitamins and electrolytes to give her? I would give her some. Mix up a high dose of it and dip her beak in it.
How old is she? Maybe she has Maerks disease?