hen losing balance and falling down

[jenson]

This morning one of our hens seems to have lost her balance and is unsteady. I have isolated her from the rest for now. She was fine yesterday but this morning something is different. She seems to still have her appetite. I picked her up and looked at her vent and it looks okay. I didn't see any Mites or red spots. Her eyes looks good. Not really sure what to do next any suggestions? She's about a year old and looks healthy otherwise. A quick online search brings up Marek's disease. If that is it, what treatment is there if any? I hope I did right by separating her from the rest? Any help you can give is very appreciated.