Keep in mind my chickens have been together for about 2 months now, have 2 hours to free range a day, and are between 10 and 14 months old. For example, when I feed my chickens hamburger bits, (which they love) the head chicken starts gets more aggressive towards the others. He just starts running after them and pecking at them for no good reason. Lettuce and most greens calm them down quite a bit and seems to mellow them out. I probably sound like sort of an idiot right now but is there any truth in it? Have you noticed anything like this?