What a wonderful ending!
If you had told me 5 months ago that a dog could be taught to leave them alone, I'd have laughed! Seriously, my beagle killed one of mine when it was about 6 weeks old. She has an incredible prey drive since we moved to the country last year. She would run up to the chicken's lot, sit, and stare at them. When one chicken came close enough to the chain link to check out the dog, BAM, she'd slam into the fence. I tried keeping her on a leash, and taking her in with me, telling her they belonged here, banning her from being near them, etc. And I did hit her with the chicken she killed. Did no good.
Anyway, one day I was fed up with it. After working for months, every single day, and no success, I was beginning to think it would never happen. I had her on the leash, she lunged at a chicken. By this time, the chickens are HUGE, and have wonderfully hard beaks.
So I turned the beagle onto her back, called my chickens over, and put a chicken on her belly. When the chicken proceeded to peck her, I wasn't fast enough to stop it. Since that day, she has NO interest except getting as far away as she can. She won't even go past the chickens to get back in the house. She is scared of chickens!!!