My chickens free range and often hang around the house. I have two rescue mutts. They ignore the chickens, will walk by them as if they were not there. It took a few months of watching them closely and telling them "no" whenever they approached a chicken (they wanted to chase and play.) They were mature dogs when I got the chickens, and already knew what "no" means -- and I am definitely the lead dog in this pack. I never used a leash, collar or muzzle, just supervised. Not necessary any more. My son lives next door and got 2 more dogs a couple of months ago, pound puppies, a lab and some little black and white purebred something. It took a lot less time to teach them to leave the chickens alone. None of them ever hurt a chicken. Since we got the last two dogs, we have had no more predator losses. None of the dogs actually guard the chickens, but they do chase off critters.
I assume there are dogs that are not trainable. I don't know anything about your breed of dog; have never owned a purebred dog, only rescue mutts. But I'd sure try training it.