As far as day protection, provide shelter for chickens free ranging. Hawks will pick them off unless they have cover. Stories of roosters or dogs fighting off hawks are far fewer than reports of hawks eating chickens. My dog (heroic chaser of raccoons and generally protective big dog) couldn't keep the hawk from eating my birds when we lived in a place with open pasture land. Now the chickens' yard has an oak tree canopy with some small bushes for shelter and though we have a pair of hawks living nearby (sometimes circling our house or perching in our trees) we haven't lost anyone to hawks. We also have an early warning system: if the hawks show up, the crows squawk, if the crows show up, the woodpeckers squawk, if the rooster sees a possible threat or hears the woodpeckers or crows he squawks, and if anyone squawks everyone heads for cover. During the day we do fine, but at night they need me to close them in.
I Lock the coop up tight at night. It's the only thing that works for sure. I lost 4 young birds to something small this year because I slacked off door opening and closing. Needless to say that when I lost them, I returned to my protective habbits and lock up every night at dusk now. The dogs keep big things out, but a rat or weasel can slip in unnoticed too easily. Make sure you coop seals well enough to keep rats out and lock up before you go to bed. It's a hassle, but it is worth it.