our small weiner dog mix had to learn the hard way by getting her butt kicked a few times by the chickens. I think the last incident we had from her was when we saw our RIR walking around witha bit of dog fur in her beak and the dog sitting on the back porch begging to come inside. Our gordon setter was a different story. We kept him on a walking leash or whenever he reached to the chcikens at all we would distract him and turn him, like the lady on its me or the dog. after a couple of weeks we would have supervised outside time with him when the birds were free ranging. eventually it got to the point that the birds could approach him and everything is fine now. We do watch him when he first goes out because he will herd them for a couple of seconds sometimes (He has a bit of border collie in him). Patience and training for the big dog, trying not not laugh at a dog getting beat up by birds for the little dog.
