That is an "old wife's tale", it doesn't work. I know...tried that when I was a kid with a dog I had, that liked to kill my birds. Same thing, an old timer told me to do it.A really old timer I know who raised dogs and chickens had a method..when he found a dog killing his birds, he'd tie the carcass around their neck for a week and make them drag it around. Not saying its 'right'..but can't argue with his results apparently.