My dad tied a dead chicken around a chicken killing dog's neck once until it rotted off.. It continued killing chickens. Next time, he beat the daylights out of the dog with the dead chicken...it kept killing chickens. Finally, he wrapped electric fence wire around a dead chicken, tossed it into the dog's house, and turned the fence on. When the dog tried to get out, it was repeatedly shocked by the dead chicken.
Next time a chicken walked by the dog's house, the dog snapped its head off just like every other time a chicken walked by.
He wasn't going to get rid of the dog, so he got rid of the chickens and that was that.
I'm not sure what the moral of the story is there, but if I had a dog that killed chickens and I wanted to keep the dog, I'd skip right over the part where you basically abuse the dog with dead chickens to try to break it and get right down to the real solution....which, of course, is to keep the dog away from the chickens and vice versa.