The best dog with chickens is one that is properly trained regardless of breed.
I couldn't agree more. Breeding also has a lot to do with it. A properly trained hyper active dog will still want to play with chickens, and the resulting broken necks can be devastating to a flock.
I suggest cross livestock guardian dogs, which unlike many other gurard dogs are people oriented, relaxed, mellow and friendly. They are bread to guard people and livestock. I've seen these dogs, (Great Pyrenees, Anatolian Shepherds, and maremmas are good examples, or mixes like can be found at coloradomountiandogs.com) correctly trained, that literally watch chickens, turkeys, goats, horses, mule, cows, pigs etc, and make sure "the family" is protected, but as soon as they catch a scent of mountain lion, raccoon, fox, coyote etc, bolt fearlessly into action to ensure it runs from the property, or comes back as a carcass.
These breeds do have some cons, but if trained properly as pups, can easily be overcome.
Hopefully that helps!
mmas