single hen left

I have a 12-year old hen. Her "friend" since birth died over 3 years ago and I got an 1-yr old chicken for her at that time. They fought for a few weeks but then have been fine together these past 3 years. The younger one, never layed an egg, while my 12-yr old has continued to lay eggs...

She is 3 years old and lived a happy life with her 5 flock mates. She was cut on her back near her tail, the others were mauled and killed. During the day I put her in a 4x8 tractor run and will continue do that until I have a new 5 or 6 foot fence built - which may take as much as a month...