Oh bless her heart! Is she able to eat and drink on her own? Is she trying to get around somehow? Chickens are pretty resilient and even one legged. Birds learn to get by quite well. If the anatomy of the leg was normal you could try a splint but if it's not normal I doubt splinting will help.you might help her out, make sure she eats and during her growing time isn't getting hurt by others and I'm sure she will learn to hop around. Or be mobile somehow by compensating her handicap.you can try a splint and see if it helps her get around.she will need your help until she learns to compensate.