I live in a very rural area in Oregon, and have always had problems with chicken hawks. Once my buff orps started having chicks, the numbers of chicks would go from 30 to 4 in one day. As you would imagine, I would go out there and bring in all the hens and chickies. They had a covered coop, but just ran around our 63 acre farm during the day. so, I heard about the CD idea, and hung up cds from all the prime kill spots, and pretty much everywhere else. It brought down the problem, but a few chicks a day were still getting nabbed. So, after going from around three roosters, thirty hens and fifty chicks to twenty hens, two roosters, and no chicks, I just gave up and built an eighty by forty foot covered run onto my coop. It is covered, so the problem is no longer a problem. As a last resort, I would just make a covered run. but the cds do work very well.