Just found one of my hens stumbling around (they free range) I checked her over and there does not seem to be an injury. I did find mites though What is the best treatment? I need to check all the other birds but getting this hen better is top priority. I have her isolated and plan to give ACV water. What else should I do? I saw her drinking. She has laid today and is trying to be a normal chicken but has issues walking. Please advise!