I vote dogs! We used to free range our birds on 10 acres every day until one day a dog came and killed everyone of them! Later, we got more, and then kept them in a portable electro-net and a neighbor pit bull came and went under the electro net, the shock barely deterred her! She killed all the 6 week old chicks (the adults had already gone to roost thank God!). Now, I only let them out when I can be out with them to watch them. Lost some to racoons a long time ago and had to change all my latches so they are trickier. I also put christmas lights around all the coops/yards for added protection. Seems the coons dont like the lights. Lost some to hawks years ago, but now I make sure there are areas they can quickly run under for cover when a hawk comes. We have a lot of hawks here that sweep by every day but everyone runs for cover and has stayed safe. No hawk attacks in about 5/6 years.