How do I stop pecking in older hens???

[chickentownUSA]

I still have a hen who is being outcast by the others. She stands alone all the time and if she is free ranging she is usually down at the house looking for me to hang with. I feel bad for her but I can't figure out why the others are picking on her?
She is not sick or new.
Any ideas of like what I could do to stop the pecking maybe something to put on her head tasting bad?

 

[SundownWaterfowl]

This is posted in the wrong section. Try posting in the section Chicken Behaviors.