Interesting article but I think there is a difference in a carnivore that has to constantly hunt for food to survive and sheep that can choose between grape leaves or a whole pasture of other weeds and grass to munch on. Wild carnivores have to be opprotunists and eat whatever they can whenever they can. It could be a long time between meals and if you have a pen full of tasty birds, I think it would be too much for them to pass up even if the last bird gave them a tummy ache. Another thought would be that you could be out of birds by the time you trained them by tainting the dead birds with the chemical.