I kill animals for a living.
I do it so others, as well as myself, can eat them. This accident of circumstance probably disqualifies me from any serious ethical discussion of meat eating. After all, I can hardly claim objectivity. Then again, who can? I live very close to the forces of nature that give (and take) life and therefore have an informed, if undoubtedly nearsighted, sense of what it is I do.
But is it ethical?
Asking whether eating meat is "ethical" is like asking whether having sex is ethical. Biological imperatives do not pander to such arbitrary distinctions.
My meat-eating is ethical, in the sense that it is not gratuitous; I understand intimately the implications and contradictions of my consumption. I know how it is that my beeves are born, the grasses they like and the ones they don't. I've saved the lives of calves and butchered their mothers in the same afternoon. I thank each for the age-old sacrifice of prey to predator and I swear they understand. I neither rejoice in the blood nor shy from it. This is life. This is ethics.
For me, my proximate, deliberate understanding of what I do defines ethical behavior as a whole: the social moderation of otherwise unrestrained individual yearnings. In my mind, eating #906 (a red mottle-face cow with upturned horns currently braising in the slow cooker) is an ethically different activity than eating a Big Mac on the run.
The fact that I feel comfortable making such a distinction indicates something fundamental about ethics: they evolve. Our current handwringing over what we eat is clearly a privilege born of abundance. Room for such ruminations are only created after the belly hasn't room for anything else. We agonize over meat consumption because we can afford to. Lucky us.
"Ethics" exist as social shorthand; a distilled collective conscience that varies with the social reality it reflects. Ethics do not stand like clean-cut traffic cops in the path of natural urges; they are more like cautionary rumble-strips as we careen down lives strewn with choices. Ethical consumption of meat, therefore, is based upon timing, circumstance, and conscientious understanding of what society deems appropriate. In modern Western culture at least, you are "unethical" if you cannot moderate a biological sexual urge. It is likewise "unethical" to fulfill biological carnivorous urges upon, say, kittens.
We have evolved from a society in which nearly everyone knew the intimate realities and consequences of eating meat to one in which nearly no one does. We have commercially outsourced the twinge of guilt, the pang of discomfort, the heart-race of witnessing a death to just a handful among us. Is there an ethical distinction between the deaths caused by a yeoman farmer who grimly butchers a hog in the fall and a minimum-wage factory worker who mechanically butchers six thousand in a morning? Many of us now see an ethical nuance. Our physical capacities to produce and consume have altered dramatically in the last sixty years; our ethical capacity to accept these realities are altering as well.
My occupation, as a result, caters to omnivores and more than a few "recovering vegetarians" who prefer (apparently) the conscientious killing I practice. I therefore raise my cattle with sentiment but cannot stray into the realm of sentimentality. I recognize that life rests upon the consumption of the unwilling. I obey this ecological truth while simultaneously working within the artificial, changeable lines society delineates. This too, is natural.
Eating meat, particularly #906, is ethical because most people think it is. That is, perhaps, about all one can say.