I have trained dedicated chicken killers so can be done. I am not a proper dog trainer either so it can't be all that hard.
When protecting your birds, always think about trying to provide layers the bad guys must get through. Most important is a secure roost and locations to nest if free-ranging. With confined birds keep ground predators out with good design and construction of coop / run. I like to use electrified fencing well for two purposes; make so predator finds challenging your confinement gets pleasant zaps and, secondly provides a perimeter of uncertainty where entering general area of where birds are kept can get you zapped. The latter is particular important again free-ranging dogs. I also maintain live-traps in high traffic areas for varmints such as raccoons and opossums. Mixed flocks (includes adult roosters) with cover can cut losses to diurnal raptors. For me the chicken friendly dogs are a combination of warning system and enforcer that backup other layers and can sometimes deliver the death blow to baddies (i.e. opossums, raccoons and foxes). I do all plus check frequently on things during night.
When protecting your birds, always think about trying to provide layers the bad guys must get through. Most important is a secure roost and locations to nest if free-ranging. With confined birds keep ground predators out with good design and construction of coop / run. I like to use electrified fencing well for two purposes; make so predator finds challenging your confinement gets pleasant zaps and, secondly provides a perimeter of uncertainty where entering general area of where birds are kept can get you zapped. The latter is particular important again free-ranging dogs. I also maintain live-traps in high traffic areas for varmints such as raccoons and opossums. Mixed flocks (includes adult roosters) with cover can cut losses to diurnal raptors. For me the chicken friendly dogs are a combination of warning system and enforcer that backup other layers and can sometimes deliver the death blow to baddies (i.e. opossums, raccoons and foxes). I do all plus check frequently on things during night.