Good thread, we are having that problem right now with a 9 month old 120# Greater Swiss... she is just playing, but can't get her to stop....
50 years ago had a neighbor who raised fighting chickens and was pretty proud of his flock. Another neighbor had a dog that killed chickens. Needless to say there was a problem. The dog owner wired a dead chicken through the dogs ear and made the dog drag it till the chicken rotted off. The dog would run and hide if he even saw a chicken. End of problem!! Probably go to jail in todays world.
My dad always tells me that my grandpa did that when my dad was a kid.... he said it worked, the dog wouldn't even look at a chicken after that.