A rooster can be helpful, he will watch and give warning, sometimes enough for the hens to get away. But he will be no match for coyote, fox, dog or just about any other predator that wants a meal. They often loose their own life in the process of trying to let hens get away. I depend on mine, he's in my avatar, primarily for hawk warning and he does that job very well. Everything else I fence out. My birds semi-free range in a securely fenced and hot wired pasture and are well secured at night. We have lots of coyote, fox and roaming dogs so my chickens would have been wiped out long ago.