We have a Pyr/Anatolian Shepherd cross who is great with our chickens, even though he's not trained to be. He pretty much ignores them. (The chickens are in a run and the dogs have no access to them.) On the other hand, our GSD is the hyper focusing, high prey drive guy who absolutely can't be trusted with the chickens. The Pyr cross shows his natural guardian instincts and could easily be trained with free ranging chickens. Like a lot of folks have said, it takes time to get them where you want them. But just be aware that some breeds can be barkers when they perceive a threat. (Ours never shuts his kibble hole when he's outside.I think it's the Anatolian in him?) A woman I met who had Anatolians on her farm said they barked all night long outside. Close neighbors might not be appreciative of the noise.