No, not even trying to supervise ranging chickens is always going to work.Any other true and tested deterrents or protection against hawks?
What improves their survival chances is having the right environment and experience of living in it. Cover is the key. Lots of cover, from blackthorn bushes to dwarf Christmas trees. The chickens learn. It takes time and some or many will die if the predator load is heavy. Those that survive and produce offspring teach the next generation how to survive.
A rooster is a must in my opinion. No, he won't fight off every, or even any predators but should at least keep the hens grouped, escorted and alerted; most roosters run.
Free ranging sounds wonderful until the reality kicks in. Some places are more suitable for than others and more importantly, some keepers are more suited to it than others. Free ranging chickens, unless one is talking about a very small area within a boundry, needs a very different approach than ranging a few hens in a small back garden.