Over the last few years I've seen debates among EA community members over whether one's economic choices as a vegetarian have any effect on the supply of animal meat produced in industry. This has always perplexed me, as Will MacAskill wrote in Doing Good Better about the mechanism by which vegetarianism is thought to decrease the supply of meat products. While one may agree or disagree with the claims Will makes, this excerpt can provide the grounds framing the discussion.
Consider ethical consumption, like switching to fair-trade coffee, or reducing how much meat you buy. Suppose someone stops buying chicken breasts, instead choosing vegetarian options, in order to reduce the amount of animal suffering on factory farms. Does that person make a difference? YOu might think not. If one person decides against buying chicken breast one day but the rest of the meat eaters on the planet continue to buy chicken, how could that possibly affect how many chickens are killed for human consumption? When a supermarket decides how much chicken to buy, they don’t care that one fewer breast was purchased on a given day. However, if thousands or millions of people stopped buying chicken breasts, the number of chickens raised for food would decrease--supply would fall to meet demand. But then we’re left with a paradox: individuals can’t make a difference, but millions of individuals do. But the actions of millions of people are just the sum of the actions of many individual people. Moreover, an iron law of economics is that, in a well-functioning market, if demand for a product decreases, the quantity of the product that’s supplied decreases. How, then, can we reconcile these thoughts?
The answer lies with expected value. If you decline to buy some chicken breast, then most of the time you’ll make no difference: the supermarket will buy the same amount of chicken in the future. Sometimes, however, you will make a difference. Occasionally, the manager of the store will assess the number of chicken breasts bought by consumers and decide to decrease their intake of stock, even though they wouldn’t have done so had the number of chicken breasts bought by consumers and decide to decrease their intake of stock, even though they wouldn’t have done so had the number of chicken breasts been one higher. (Perhaps they follow a rule like: “If fewer than five thousand chicken breasts were bought this month, decrease stock intake.”) And when the manager does decide to decrease their stock intake, they will decrease stock by a large amount. Perhaps your decision against purchasing chicken breast will have an effect on the supermarket only one in a thousand times, but in that one time, the store manager will decide to purchase approximately one thousand fewer chicken breasts.
This isn’t just a theoretical argument. Economists have studies this issue and worked out how, on average, a consumer affects the number of animal products supplied by declining to buy that product. They estimate, on average, if you give up one egg, total production ultimately fassl by 0.91 eggs; if you give up one gallon of milk, total production falls by 0.56 gallons. Other products are somewhere in between: economists estimate if you give up one pound of beef, beef production falls by 0.68 pounds; if you give up one pound of pork, production ultimately falls by 0.74 pounds; if you give up one pound of chicken, production ultimately falls by 0.76 pounds.
MacAskill, William, Ph.D. "Why Voting Is Like Donating Thousands of Dollars to Charity." In Doing Good Better: How Effective Altruism Can Help You Make A Difference, 87-88. New York, NY: Penguin Random House LLC, 2015.
The economic impact of vegetarianism or veganism is only one factor in the decision of whether one should become a vegetarian or vegan, but an important one. Further discussion of why to become vegetarian on economic grounds within the community can be found here.
That some chickens will never be born at all is the goal, as:
it's believed those chickens born would have lives of only suffering, not redeemed by happiness;
the degree and constancy of the suffering is so great considerations of preferences the chicken may have, like a 'will to live', are overridden by the preference/desire to be free of suffering;
the expected consensus is we know enough about animal minds to conclude they have preferences like the instantaneous desire to be free of suffering in any given moment, but we don't have sufficient reason to believe they abstractly think of the future, and meaningfully have a 'will to live';
the collective experience of the farm animal rights movement has been decades of reforms of factory farms remain unenforced or are insufficient to overcome the above considerations about how the lives of chickens on factory farms will never be worth living.
So the goal of some effective altruists focused on present and near-term future non-human animal well-being isn't to advocate for the animal's rights so much as it is to mitigate factory farming as an industry. This is from a perspective of EA from years ago, when Doing Good Better was published. There has been an empirical revolution within effective animal advocacy since then. The evidence has borne out employing messaging focused on systemic change over individual dietary/behavioural change, and not splitting hairs in messaging based on ideological differences internal to the animal welfare/rights movement. So if one cares about the rights of species to not go extinct, one doesn't have to fear the movement strategy implied by the OP, as effective animal advocacy (EAA) organizations are mostly not pursuing that strategy anymore. Given how expansive factory farming is in developed Western countries, and how it's expanding in developing countries, it appears factory farming, and thus the species of farm chicken, isn't going away soon. That stated, I've no reason to think effective animal advocates would object to preserving the genome of the farm chicken, or rearing individual farm chickens under humane conditions, e.g., at an animal shelter or hobby farm.
Of course peers of EA outside the movement have weighed on the topic, disagreeing with the consensus EA position on either side. An argument against vegetarianism and for the continuation of factory farming exists in the logic of the larder, as laid out by Robin Hanson and others. On the other side, another animal liberation movement called Direct Action Everywhere (DxE) thinks EAA doesn't go far enough. While I haven't followed them closely, and so I find their end goals confusing, I believe DxE's strategy is to mitigate factory farming isn't to have them not be born into net-negative lives, but raising sufficient public consciousness global human civilization will at some point in the future literally directly liberate all presently factory-farmed animals, presumably to freely roam the Earth.
*"effective animal advocacy" is the term for the interstitial movement emerging from the combination of effective altruism and the conventional animal welfare/rights movement.
Were chicken preferences measured by EEG or choice? see also may comment above.