I have a 9 month old NH hen and this morning when I went to open up the coop everyone went out except her. I went into the coop and picked her up and she didnt flap her wings or move her feet. Then to tesdt her I put her on a perch and she started to wobble and she couldn't keep her balance. She has been eatong and drinking fine and there are no physical marks on her to show she was attacked. Does anyone know whats wrong with her and what I should do?