This morning while letting my five week old chicks play in the yard they suddenly made a bee line to a bush and hid. When I looked up I saw a hawk glide on by. This just further cemented in my mind that I had made the right choice with my "fort knox" approach to Tractor Design. I realize baby chicks are in danger of hawks but I've never seen anyone mention adult chickens being targets which leads me to believe that at some point they are not considered prey. At what age or at what size do chickens stop being hunted by hawks?