Just because we would pick the easy and visible prey does not mean the predators do...from what I've read or seen, they usually nab the more natural looking prey or the obvious loners that are far from the flock.
I had a bunch of red goldens let loose to free range. They stay around like chickens. It was awesome to watch them display a fuller range of natural behavior. For example, on free range they showed being able to walk along branches, like a monkey does. They'd grab the thinnest twigs and reach out to the branches on an adjoining tree and walk over.. something chickens cannot do and you just don't get to see in an aviary... The males also showed courtship behaviors they never did while confined.
Anyways the point for responding to your comment is, they all did great spring time through mid-fall..... until the winter hawks showed up. ALL of the females and juvenile males were killed, while the fully colored adult males were left alone. For years..... Hawks never touched those.
I've always thought it was because the males did not resemble any of their natural prey, too different looking. I can imagine that some hawks would 'learn' to give them a go though as hawks will go after chickens, so...