I've had a variety of dogs in my 60+ years. My black lab was a wonderful hunter, and she killed a couple of chickens when she was a pup. In her later years, she never bothered them at all, although she was a wonderful pheasant hunter. I've also had an Airedale, a Walker coon hound, a pitbull, many Rat Terriers (have one now). Most of them killed a bird or two when pups, but quickly learned to leave the birds alone.
We now live in a very small town. Our neighbor is a city policeman who has a yellow Lab. She barks incessantly, and is NEVER exercised or paid any attention to. Another neighbor has 3 mutts that bark even worse than the Lab. They live in a medium sized fenced yard, and never leave it. I have about 20 bantam chickens in my fenced yard. The roosters crow, and the hens cackle after they lay their eggs, but nobody complains, because the dogs' barking drowns out my chickens' sounds.
But---back to the original question: Yes, dogs can definitely be taught not to kill birds. It takes time, and patience, but it can be done. And---puppies are the worst for "playing" with chickens, but when they mature, they get better quickly.
The worst thing I've ever had that could not be trained not to kill was a runty kitten that my daughter rescued. It killed many of my rare peachicks. I now have bad feelings for all cats.
