I have not consumed the flesh of tetrapods since I was in college. It is not, however, because I believe it is morally wrong in principle for humans to eat meat. Biologically, we're omnivores, and animals eat each other. That's nature. No, it's because of the way meat is produced in our society. Here is an important report that has gotten far too little attention, called "Putting Meat on the Table: Industrial Animal Farm Production in America." It was produced through a grant from the Pew Charitable Trust, which created the Pew Commission on Industrial Farm Animal Production. Here are some brief excerpts from the introduction. I wish I could present more, but do read the whole thing.
Over the past 50 years, the production of farm animals for food has shifted from the traditional, extensive, decentralized family farm system to a more
concentrated system with fewer producers, in which large numbers of animals are confined in enormous operations. While we are raising approximately the same number of swine as we did in 1950, for example, we are doing so on significantly fewer, far larger farms, with dramatically fewer farm workers. This production model—sometimes called industrial farm animal production—is characterized by confining large numbers of animals of the same species in relatively small areas, generally in enclosed facilities that restrict movement. In many cases, the waste produced by the animals is eliminated through liquid systems and stored in open pit lagoons. . . .
This transformation, and the associated social, economic, environmental, and public health problems engendered by it, have gone virtually unnoticed by many American citizens. Not long ago, the bulk of the fruit, grain, vegetables, meat, and dairy products consumed by the American people were produced on small family farms. These farms once defined both the physical and the social character of the US countryside. However, the steady urbanization of the US population has resulted in an American populace that is increasingly disassociated from the production system that supplies its food. Despite the dramatic decline in family farms over the past 50 years, many Americans, until very recently, continued to think that their food still came from these small farms.
While increasing the speed of production, the intensive confinement production system creates a number of problems. These include contributing to the increase in the pool of antibiotic-resistant bacteria because of the overuse of antibiotics; air quality problems; the contamination of rivers, streams, and coastal waters with concentrated animal waste; animal welfare problems, mainly as a result of the extremely close quarters in which the animals are housed; and significant shifts in the social structure and economy of many farming regions throughout the country.
There is also a substantial environmental justice component to this problem. In the new American Journal of Public Health (subscription only) Steve Wing and colleagues tell us that "Industrial hog operations in North Carolina are disproportionately located in communities of low income people and people of color, where inadequate housing, poor nutrition, lack of access to medical care, and simultaneous exposure to other environmental and occupational hazards may exacerbate their impact."
Other negative externalities of industrial meat production stem from its immense resource intensity. Eight times as much grain is ultimately consumed when people eat meat, than when they eat the grain themselves. This grain is grown using diesel powered tractors and synthetic fertilizers, then trucked from cornfield to hog farm, driving up the cost of both vegetable foods and fossil fuels, and polluting the atmosphere. In rural China, people once kept pigs and fed them field and kitchen waste. Today, they more and more eat pork from factory "farms," and that is an important reason for the rising cost of food and fuel in the world. In the U.S., dairy farmers would keep their cows in pastures, and supplement the forage with corn they grew themselves, and fertilized with their own cow's manure. (That is still done, by the way, in Windham County.) Today, more and more, dairy "farms" are vast industrial operations that keep their cows in pens, feed them grain trucked in from elsewhere, and store their waste in lagoons from where it is eventually discharged into surface water.
It isn't morally wrong for people to eat animals that have been permitted a normal life, but factory farms, in my view, are inhumane. I have discussed the problem of antibiotic resistance resulting from the practice of routinely putting antibiotics in animal feed, which is necessary because of the crowded and unsanitary conditions in which animals are kept. The social, environmental, and moral costs of this industry constitute an atrocity.
Don't patronize it. If you are going to eat meat, find out where it comes from. It won't be easy to find ethical sources, believe me. The easiest and best thing to do is just stop.