older hen behaving strangely

[Animalfisherwoman]

Try introducing with the younger flock with multiple hiding spots/food/water dishes. Could be they try to run from her...

 

[alexa009]

Do you have a picture? Pictures describe and show a lot. It could possibly be anything, if she is acting lethargic then she could be sick or having egg complications such as egg bound or prolapse of the uterus which is very common in hyline hens that hit around 2 years of age. Pecking order could be a factor too, but usually there is a difference in personality with the pecking order and a sick chicken. A sick chicken will appear lethargic, listless, hardly moving. If you were to try feeding a chicken who is being picked on, they will act like their typical self.

 

[Cecilia of Finland]

Hi, I have now introduced her with the younglings and It worked. She is back to her old self, no longer afraid of everything that moves and no longer overly attached to me. She quickly established her self as the highest in the pecking order, the younglings didn't seem to mind.

Thank you for the help. It seems like you were correct about the root of the problem.