This I found to be true. We ended up with a german shepard cross puppy about 3 years ago.She was a castoff. I am NOT a dog lover, but the kids and dh had wanted a dog for a long time. I had been resistant, but caved. As puppy grew she went thru about a 6 month period of "playing" with my chickens. EVERY time I bodily picked her up and was aggeressive with her. I was ready to get rid of her all together. A lot of family disharmony for that stretch of time. However.... As she grew up after about the 6 th time in that 6 months that I DID get her IN the act. She stopped. Now she completely ignores the chickens and can be trusted with them. Still not a dog lover, but I can hear the difference in the dogs vocalazations, and she will use a certain yip that tells me SOMETHING is messing with my chickens. She is never wrong and only makes that sound regarding my chickens.Unless a dog is caught IN THE ACT punishment is ineffective. A dog is not going to relate "chicken parts" and a beating to killing chickens. If you looked at the pictures, these are small dogs so "beating it with a 2X4" would severely injure if not kill it.
This would be considered abuse, regardless of where you live.
I have "heard " the dead chicken or chicken parts theory when i was ready to get rid of dog. Lots of people told me it worked, I never tried it. But catching her IN the act and yelling at her to leave MY chickens alone, that worked for me and this dog. Since I DON"T have tons of expereince with dogs, I can't say if it works with all dogs, I tend to think it is varies greatly depending on dog. I didn't use a 2 by 4 just my voice and hands. I picked her up yelled and screamed and then threw her down. Again I am not putting myself out as a dog trainer, just saying I know catching them in the act DOES work, but took more than once.