The vast majority of the animals we eat are raised in factory farms. These are not humane places, but I will spare you the grim details here. The key issue is that they inflict severe and unnecessary suffering on animals merely for the sake of slightly cheaper produce. If you care about animal welfare—and most people do, as we see whenever someone mistreats a pet—then the conditions of animals in factory farms give you strong reasons to make some changes to reduce the amount of animal products in your diet.

However, this argument applies much more strongly for some animals than for others. This is because there is considerable variation in both the conditions animals are kept in and the number of animals needed to produce a given number of calories. As a consequence, some types of animal produce involve a lot more animal suffering than others. Let us consider these two sources of variation in turn.

The first variation is in the animals’ quality of life. Some farm animals live much worse lives than others. Of all the animals raised for food, broiler chickens, layer hens, and pigs tend to be kept in the worst conditions, by a considerable margin. Bailey Norwood, an economist and agricultural expert, has estimated the welfare of different animals on a scale from –10 to +10, where negative numbers indicate that it would be better, from the animal’s perspective, to be dead rather than alive. Norwood rates beef cattle at 6 and dairy cows at 4. In contrast, his average rating for broiler chickens is 1, and for pigs and caged hens –5. In other words, cows raised for food have lives that are comparatively good, in contrast with chickens, hens, or pigs, which suffer terribly.

The second variation is in the number of animals needed to produce a given number of calories. A cow will feed an entire family for several months, whereas a chicken can be eaten in a single meal. In a year, the average American will consume the following: 28.5 broiler chickens, 0.8 layer hens, 0.8 turkeys, 0.37 pigs, 0.1 beef cows, and 0.007 dairy cows. On the basis of these numbers, it would seem that cutting out chicken meat has a far bigger impact than any other dietary change.

Things are not quite so simple, however. Most broiler chickens only live for six weeks. Cows, by contrast, live for several years. Insofar as we care about how long the animal spends in unpleasant conditions on factory farms, it’s more appropriate to think about animal years rather than animal lives. If we adjust the figures in the previous paragraph so that they account for the varying life spans of the different animal species in factory farms, the number of animal years that go into the average American’s diet are as follows: 3.3 from broiler chickens (28.5 chickens consumed, each of which lives six weeks), 1 from layer hens, 0.3 from turkeys, 0.2 from pigs, 0.1 from beef cows, and 0.03 from dairy cows.

Combining these two considerations, we arrive at the following conclusion: If you are only reducing the amount of meat you consume—being a “reducetarian” rather than going entirely vegetarian or vegan—the most effective way to reduce animal suffering is to stop eating chicken, then eggs, then pork. Targeting the animal products that cause the most suffering insures that your efforts have the highest payoffs in terms of animal cruelty avoided. This shows the importance of effective reducetarianism, an example of a general approach I call effective altruism.

Calculating Effective Altruism

As the phrase suggests, effective altruism has two parts. As I use the term, altruism simply means “improving the lives of others.” Many people believe that altruism should denote sacrifice, but if you can do good while maintaining a comfortable life for yourself, that’s a bonus, and I’m very happy to call that altruism. The second part is effectiveness, by which I mean doing the most good with whatever resources you have. It is important that effective altruism is not just about making a difference, or doing some amount of good. It’s about trying to make the greatest difference you can. Determining whether something is effective means recognizing that some ways of doing good are better than others. Just as science consists of the honest and impartial attempt to work out what’s true, and a commitment to believe the truth of whatever that turns out to be, effective altruism consists of the honest and impartial attempt to work out what’s best for the world, and a commitment to do what’s best, whatever that turns out to be.  — WM

If rights activist were given absolute power over farm animals…

They would still face some tough choices. They could choose to take all existing farm animals and put them in a wildlife preserve, away from the “greedy carnivores” who wish to put animals in cages and eat them. Still, a host of questions would arise requiring difficult trade-offs. Should people remain responsible for feeding the animals? Should we try to prevent wolves from eating piglets? Are the animals to be allowed to breed, and if so, what should be done when the population exceeds the capacity of the preserve to feed them? Should we let natural diseases run their course in the preserve, or should we intervene? If two bulls are fighting, should they be stopped before one is hurt? What do we do with a wild bull that gores a human? The point of these questions is not to mock animal rights activists but to point to the fact that, regardless of whether human eat them or not, farm animals are dependent on humans and their choices. The complete abolition of livestock as property does not make the choices easier, unless the definition of abolition includes the complete extinction of farm animals. However much animal rights advocates associate themselves with the abolitionist movement of the 19th century, livestock can never really be liberated. Livestock must be owned and cared for, or they will become practically extinct. —F. Bailey Norwood and Jason Lusk, Compassion by the Pound: The Economics of Farm Animal Welfare