There was/is a thread where a fellow who trained dogs discussed using the electric shock collar. The key was not to give the dog the shock via the collar when the dog begins to move aggressively towards the chickens; then it's too late from his perspective. Rather, it was close observation without the dog knowing he was being observed. Then when the dog even looked at the chickens with interest, it got zapped while thinking about them. But since the owner/trainer was not necessarily there from the dog's point of view, each dog was trained to adhere to this sort of behavior even while the owner/trainer was absent. (Remember, the training took place largely without the person directly and verbally intervening from the dog's viewpoint.)
In other words, the dogs learned that even thinking about getting after a chicken resulted in a nasty, throw me on the ground jolt. And he didn't mess around with a low shock first and then slowly build up power until the dog's comfort level was breached. He nailed it hard each and every time so that even thinking about the chicken chase was to be avoided at all costs from the dog's viewpoint. Worked, worked quickly and end of story. Others that tried it got the same positive results.
