Nellie is making a weird kind of coughing/sneezing kind of yelping noise. This will happen once or twice and then not again for about 15 or 20 minutes. Also her breathing sounds like a moaning sound sometimes. Right now she's breathing quietly. She's just standing in one spot. Her eyes and beak look clear to me, I don't see any drainage or dampness. I took her away from the rest of the flock and brought her into the house where it's warm. We've had our first cold snap of the year and we've had frost the last few nights. I haven't seen her eat or drink anything since I brought her into the house an hour ago. I sent my DH for the store for cider vinegar. But how much do I put into the water? I don't have any medicine on hand. I can get something tomorrow. The rest of the flock is okay. This came on suddenly, she was okay yesterday. Any advice would be greatly appreciated.