This is one method that I absolutely would not employ. This leaves the dog alone with the chickens, even though in a fenced environment. He learns that he can bark, lunge, and engage in other aggressive behaviors to get the chickens to cluck, scream, flap their wings, and otherwise react in ways that are stimulating for him. All this while he receives no correction from his owner for that destructive behavior.
I would put him on leash, and take him with me to do chicken chores. make him lie down. give verbal praise when he avoids looking at chickens, or remains calm in their presence. My dog has high prey drive. I tried this technique for the better part of a summer. It works for a lot of people. In her case, I had to resort to a behavior modification collar on vibrate mode. 2 collar reprimands were all that were necessary.
The last time I mentioned employing such a collar on BYC, I was called all sorts of names for being so "abusive". Is it more abusive to have a dog who can be trusted around birds, or have a killer dog???
Lazy gardener's experience mirrors my own. I was very embarrassed that I couldn't train our cattle dog mix, after being a training guru with our previous dog. It took 2 good shocks to train her not to chase chickens. After those 2 shocks, I set the collar on vibrate & used the vibrate mode anytime she appeared to show interest in the chickens. I only had to do that a few times. Soon after, I returned the collar to the person I borrowed it from. It's been over 1 year & all is well. In fact when I recently got new chicks, I was concerned that she may not remember that these little things are chickens & can't be chased. No problem!