Handily, most of the predators in my area are simply repelled. I have been doing this for some time and have a good number of birds in very close proximity to a lot of wildlife. Most of my birds spend their entire lives in a field. Every once in a while a predator figures out how to defeat my repelling systems. This occurs not every year but when it does lethal force used to prevent loss of chickens. Flexibility in approach should never be ruled out. Going only to killing or never doing it is not something I see in people that keep birds for long periods of time.