Sorry that your hen is still having the issues—I am really sorry. It is hard to know if she could have been injured, has a riboflavin deficiency, or if she may not have had a successful Mareks vaccination. About all you can do is to give the vitamins and the anti-inflammatory medicine, and see what happens. If you should lose her at some point, then I would get a necropsy to look for Mareks. There is also a pcr blood test that is available for $20 at this lab in Texas:
http://www.vetdna.com/
http://www.vetdna.com/