Hawks are opportunists. I have much experience with them, as in additional to LF and bantams I have kept racing pigeons for a long time. The pigeons are more likely to be taken than even bantams. That said I do lose many chickens to hawks each year. My birds free range from sun up to sun set, when they are locked in for the night. In my experience the Kestrel is not a factor even with the pigeons. I have had Sharpshins kill pigeons and attack wild birds at my bird feeders. They are not large enough to carry a pigeon off. My primary hawk of concern is the Goshhawk. They are large and can easily kill even LF chickens. They are a surprise attack predator, and they in most cases do not circle way up high and drop on their prey. They come in at tree top height or lower very fast and catch the prey bird by surprise. I would assume that a Coopers hawk or Redtail would hunt in much the same way. Once the hawk has found a location with a food source they are going to come back regularly, and I am convinced that as they migrate they can recognize buildings that are associated with a meal source. I do not advocate killing them. They are protected, and the fine for killing one can be $10,000. The only sure protection is a pen that is covered with wire.