I have an adorable little black-and-white mottled serama pullet named Magpie who suddenly lost her ability to walk. She is a few months old and was living in a pen in my house with a few other seramas her age up until a few days ago, and I just transitioned her outdoors. She and her three hatchmates were doing just fine with the other seramas and enjoying the outdoors, and then suddenly I found her in the henhouse unable to walk. She eats and drinks well, has no visible injuries, and her toes are not curled. She is sitting on her elbow joints more or less and they're getting red from the pressure. Her legs are held somewhat stiff underneath her, but I can stretch them normally. Then they snap back into their previous position once I let go. She cannot stand up. She keeps her wings somewhat outspread when sitting there to keep her balance. Her eyes are clear, she otherwise seems healthy, her hatchmates that were exposed to the exact same everything are fine, and I'm just baffled here! For now I have her indoors on a heating pad, eating one or two whole hard-boiled quail eggs a day (including the shell) as well as the usual Flock Raiser. I'm planning on getting some Polyvisol and plain yogurt, and she's going to tag along to the vet's today because I'm bringing in some wildlife I'm rehabbing anyway, but I'd love all the suggestions I can get. I really don't want to lose her... She is absolutely darling and I'm quite attached. What could be causing this so suddenly, and how can I treat it?