While environmental configuration and flock management are certainly valid considerations you're forgetting a few things; population density of aerial predators, population density of alternate prey animals and ease of catch of your chickens v. the alternate prey animals all play a major role in who has hawk problems and who doesn't as well.
I would agree with you however, that in most areas a fort knox chicken run is not necessary to keep losses to predators (aerial and otherwise) low. (Note: "low" not "nonexistent".) If I had to write a guide to fighting predation without the use of heavy-duty fencing and covered runs it'd probably go a little something like this:
- Choose chickens that wear natural protection 24/7. A bright white chicken stands out against every background except snow. Unless you live at the north pole avoid bright white chickens.
- It's called "survival of the fittest" not "survival of every chick that hatches". Allow nature to take her course. If the chicken is too dumb to take cover you probably don't want it reproducing in your flock, creating more stupid chickens that don't take cover!
- Provide natural and/or artificial cover. Large bushes, trees, thick, varied gardens. This way the chickens that are smart enough to avoid predators have somewhere to do that.
- Don't make your farm easy pickin's. You're not running the neighborhood buffet. Activity deters predators, keep a farm dog, some other livestock, be seen in the yard throughout the day if you can. Utilize scarecrows, pie plates, a radio, etc. Know which predators are most common in your area and tailor your tactics to that animal.