In the past couple of days my white serama that hangs out with all the other bantams and big chickens just started hiding out alone more, then today she was just in one spot all day, not pecking or scratching. She is shaking a little and her head looks off to one side, like her neck is swollen or something funny there, but no signs of any injury. She is also walking off balance. All the other chickens seem fine. Any ideas on what this could be? For now I have put her in a comfy cage near her friends so that no one will bother her, if the big chickens decided to.