Poor lovely. Was her flesh/skin frozen or just the feathers? How much was submerged in the ice? She may only suffer frostbit on her skin, or it could be worse. Chickens have survived their wings torn off by predators, so, even if her actual wing froze, I would say she stands a good change. If she was weak to begin with, causing her to be stuck there and get frozen up, that could be another story. You will need to monitor her closely and observe closely for damage to the wing. Honestly, this may be a wait and see thing, but if you offer her the best supportive care possible and tend to her wounds, if she ends up with any, I think that is her best chance. I will be watching and hoping for the best.