The last few days I have had ravens swooping down to try to get my chickens. They killed one of my bantam hens and also tried to get one of our Rhode Island Red hens today . My chickens are not free ranged unless I am watching them and they have a covered run area but some of them get out and I am worried I will lose more... I also have khaki campbell ducks that free range all over our farm. What should I do ? Can I put up something to scare the ravens away ? Thanks !!