My little chick is shaking her head every second from side to side and seems to have food in her crop - she is a week old and has eaten oats and chick feed. I massaged the crop and it seems hard-ish but the food can be moved around in there. I am scared for her as her sister died today (lethargic, not eating or drinking) and I don’t want her to too. She eats and drinks fine. Should I buy apple cider vinegar? We have malt vinegar but I’m not sure it would be the same. What is wrong with her?