Professional dog trainer here. Swift, severe, certain punishment is dog abuse. Enlightened people use positive reinforcement methods to get the point across--it works better to teach a dog respect than to teach fear.
Much respect to your skill set, If you are anything like the lady that tried to help me I was just impressed how this very little person almost instantly had my girl in check. I was obviously the weak link.
However I find it very hard to have a positive response to dead or dying chicken in Sally's mouth. You have to deal with it at the exact time, as otherwise they have no idea why they are being punished.
She gets a LOT of positive actions at other times, and I know not to call her afterwards to get punishment as that would make her unsure about the come command.
But sorry dog lovers, if she does make a move, or accomplishes a kill she gets her just rewards.
On a positive note after our last kill session about 6 months ago she seems to have almost learned the lesson. Today I walked her around the chickens and while she pulled to sniff poop and scent trails she didn't make any move towards the girls... not even the little chicks. But I wouldn't trust her without me being there. She definitely has hunting traits. When loose in the bush she's off everywhere with her nose to the ground, or sniffing the air. Lizards have to be fleet of foot, and she's very fast at catching flies.