You might take her to a vet. Where I live, in Massachusetts, the wild animal sanctuary has a vet that will see chickens. The wild life sanctuaries see a lot of birds because a large part of their patients are migratory birds that have had problems. The vet at the one in Mass, called the Odd Pet...
I have a hen, Clover, who has similar symptoms. Her feet are curled up underneath her and she can't stand or walk. She does manage to flap her wings and flop around some. I got her from a neighbor who said that her flock was attacking her as chickens do when one looks hurt or limping. I took her...