I couldn't agree more. I hope she gets better.It is very possible that she has a deficiency but I suspect that she either has a calcium deficiency or the inability to properly process calcium due to a vitamin D deficiency. My recommendation is to separate her from the flock but in a manner that the flock can still see her and she can see them. Get some liquid calcium usually available at a pet store or online. Follow the directions for mixing it in her water. If she has a calcium deficiency using the liquid calcium is the fastest way to get her calcium levels back up.
If she doesn't start improving in a few days, you might want to try giving her some vitamin D also.