Hard to say if she will ever stand or walk. Since we are not completely sure why she is in this condition, we can't know the outcome. I look at it this way...is the bird living a decent life....is the bird strong enough to continue on and does it wish to? Can you take care of a disabled bird? She may heal, she may not.
Right now I am dealing with an old hen that had a stroke. She has lost all use of her legs, and lives in a low basket, but is still happy to be alive, loves to lay in sunbeams, gets overly excited for treats and truly enjoys life yet. She is a TON of work to keep her clean, move her around, keep her fed, watered and warm. But I WANT to do it and will continue until she wants to give up on life and passes or I have to put her down because she is suffering. I keep her in a basket with towels to keep her upright, food and water right there for her to eat and drink all day long. She is still in the flock and even flock leader! But she has NO use of her legs at all.
Suffering is hard to tell in a bird. If they still enjoy eating, and eat well, drink well, seem alert and no obvious pain, they no they aren't suffering. But if they are disabled, they do need extra care and attention. They can still do chicken things if given the proper care. If you are unable to give them this much time and attention, then sometimes the best option is to put them down. You need to analyze the situation.