chicken only pecks others in warmer weather

Is it feather plucking or general aggresiveness Ryan?  It's breeding season now so a dominant hen might be assuming the role of the cockerel and establishing herself at the top of the pecking order ('scuse the pun  ) 

If it's feather pecking you can buy beak rings which stop the birds closing their beaks fully and so they can't get a decent grip to pull feathers. They don't interfere with eating, drinking or preening, but she won't like it at first so be ready for a bit of outrage until she forgets about it 

Have you checked for lice? They may die off in cold weather and become very active in warmer weather.

cant see any sighns of lice and feathers seem to be coming back slowly thought at first the beak ring would upset the hen but it doesent seem to notice it thank you for the help