For 2 years now we have put a fallen down branch into the run area. Good sized girth with several branches protruding. Stable enough to hold several birds weight. This is like an outdoor roost for them! They even challenge each other for the best spot and kind of like king of the castle until you get knocked off. If your chickens become bored you might want to consider this or something similar. It will keep you amused as well! 
