Two types of animal right arguments

It seems to me that meat can be criticized in a couple of different ways. One of them is just to say that somehow animals have the right to life and we shouldn't be killing them. Another would be to say that we have the right to kill animals, but that meat-producers do so unethically. The Kashrut or Kosher Law of Judaism seems to be, at least in part, based on this motivation; the eating of meat isn't wrong, but unless it's killed properly, it shouldn't be eaten. And, in Alpha, the actual world, most animals are not slaughtered properly.