Egg binding can rarely sometimes cause leg weakness. Hopefully, she has an injury that might get better with rest. I would try to pick her up occasionally to see if she is able to stand. It probably would not hurt to give her some vitamin B complex 1/4 tablet daily crushed onto food.
Have you added any new chickens to your flock in the last few months? Does she still lay eggs? How long has she been showing these symptoms? You may want to check her for being eggbound by inserting a finger inside her vent an inch or two to feel for a stuck egg. Chicken slings may be used to...
Sorry about your chicken. So at present, she can get up and walk some? Does she hold the sore leg up, or does she try to put it down when she walks? Can you look over her footpad for any bumblefoot scabs or cut, and the entire leg for swelling, bruising, and redness? Hopefully, she has sprained...