I have the worst dog ever! She wants to kill everything with fur or feathers. However, for some strange reason we have been able to curb her attention away from the girls.
Our dog Penny can't be around other dogs at all. We've tried shock collars, choke collars, bitter apple, positive reinforcement, and slapping on the butt. Still no luck.
We let out chickens "free range" in the backyard, along with our dogs. The first week or two was horrible, nothing butt yelling and chasing. One day I was watering the garden and instead of yelling, I hit the dog with the hose (not the actual hose). Turned up the water to high and gave it to her. After about a week of "learning" she has not desire to chase the girls. The only side affect, she runs the other way when I water the garden. Small price to pay, but she associates chickens with getting sprayed with water. If I could only take the hose to the dog park.
Hope this helps. My last resort.