Participants could see the title of the survey in their mail, before opening the survey. The participants get rewarded with a small value coupon when completing the survey, so I don't expect a pro-animal welfare selection bias. There was a question about active involvement level on animal welfare issues. Half of the respondents indicated to are not involved with animal welfare at all, 4% indicated high involvement, meaning e.g. eating no meat. Others had involvements like occasionally signing animal welfare petition. These statistics seem to be right, representative to the Belgian population. The survey was short, so not much difference between completion times. No significant differences in welfare range estimates were observed between people with more or less involvement, men or women,... Only relevant (statistically significant) difference: people with less active involvement had smaller negative estimates of broiler chicken welfare. I expect this to be a fluke, but again this indicates that the survey does not really have a pro animal welfare bias. Could be some social desirability bias, although I expect this to be small in anonymous online surveys of members of a marketing research company panel.

Good criticism, David. Although not entirely clear to me yet, especially the part in brackets. I'd say if we give up the assumptions of valence symmetry and scale linearity, matters are even worse for the chickens, because I expect most people to have a more negative skewed welfare scale (i.e. the negative side of the scale having a wider range than the positive side). If negative experiences can be 10 times as intense as positive experiences, a -3 welfare of a chicken would actually be a -30, i.e. 10 times larger in magnitude than a +3 welfare of a human. Also the answer options of the animal welfare range are skewed in favor of animals having a welfare range lower than 1. Hence, many aspects of the survey indicate that the suffering of broiler chickens is underestimated.

I don't think the revealed preferences of consumers are good indicators of people's estimates of the welfare levels of farmed animals, because of many reasons

1. Cognitive dissonance: see the meat paradox and the mind denial bias of meat eaters. Consumers simply don't think and don't want to think about the suffering of the animals they eat. Also, almost 10% of respondents say the survey makes them want to eat less meat. This is in line with personal experience I have with conversations with people on the streets. Just asking them whether they believe a chicken has a positive or negative welfare makes them more inclined to say they want to reduce their meat consumption.
2. The revealed preference is not only dependent on the estimated welfare level of an animal, but also on the moral weight one gives to animal welfare and other things unrelated to animal welfare. Perhaps a person beliefs that farmed animals suffer a lot, but doesn't consider animal suffering as important when it comes to food choices. Or the person believes that eating meat is necessary and one is allowed to eat meat at all cost, no matter how high the animal suffering is (comparable to the belief that Israel has an absolute right to self-defense and is allowed to defend itself against Hamas terrorism by attacking Gaza, no matter how high the cost to Palestinians).

I just conducted a survey (representative sample Belgian adult population), according to which most people believe the welfare range of a bird is equal to the welfare range of a human, and the welfare level of a broiler chicken is negative. https://forum.effectivealtruism.org/posts/MP4rNBu6ftG4QE3nL/the-suffering-of-a-farmed-animal-is-equal-in-size-to-the

Hence, Kyle's estimates of the welfare of farmed animals, based on Rethink Priorities median welfare range estimates, are underestimated according to most people (in Belgium). Most people would have to come to the conclusion that net global welfare is even more negative and more declining than what Kyle's calculation suggests. 

Hi Laura

"In fact, one of our welfare range models (the undiluted experiences mode) that feeds into the aggregate estimates tends to produce sentience-adjusted welfare range estimates greater than 1 under the theory that less cognitively complex organisms may not be able to dampen negative experiences by contextualizing them." -> I'm not sure if this is correct. I'd think that the welfare range remains equally large if someone's 'suffering dampening capacity' increases. That dampening capacity is like a painkiller, but someone who has more access to painkillers does not have a smaller pain range. If a person simply decides not to take a painkiller, or not to dampen suffering, that person's suffering remains large. Furthermore, this dampening capacity argument violates the valence symmetry assumption, unless someone with a large suffering dampening capacity also has a large happiness dampening capacity and cannot help but to dampen his happiness just like he cannot help but to dampen his suffering. But why would a person dampen happiness? 

I have some concerns about animal-welfare labelled meat, that it could be counterproductive. See this study: https://www.tandfonline.com/doi/full/10.1080/21606544.2024.2330552

Most non-vegans don't take vegan B12 supplements. That means this vegan product is excluded from the non-vegan's diet. The reason why non-vegans exclude it (whether they don't like it, consider it as immoral...), is not important because reasons are not health related. Whether or not someone who doesn't take the B12 supplement categorically refuses to take it, has no impact on that person's health.

I was pointing at a non-vegan bias in the way how you framed your argument: that a vegan diet is restrictive. But non-vegans also eat a restrictive diet, as they don't eat (and often refuse to eat) vegan foods. Vegans don't eat non-vegan sources of B12, and non-vegans don't eat vegan sources of B12. 

Your bias is comparable to a native English speaker who has an English bias and claims that French is a difficult language because the French people don't use those simple words like "door" and "table". So when you want to speak French, you first have to learn new words. But the fact that the French language doesn't use the words that you use, doesn't make it a difficult language. For native French people, French is an easy language.

So the crux is: a vegan diet is not difficult, but changing diet is difficult. For vegans (who learned how to eat vegan), a vegan diet is easy, just like a non-vegan diet is easy for non-vegans (who learned how to eat non-vegan).

I agree with your two sentences, but the first one is very ambiguous. You mention someone with a B12 deficiency. The way I see it, both vegans and omnivores remove sources of B12 from their diet: the vegan doesn't eat animal products that contain B12, the omnivore doesn't eat B12 supplements (or B12-enriched products that are suitable for vegans). Many omnivores even refuse to eat those vegan B12 supplements, just like vegans refuse to eat meat. Now you have someone who doesn't eat either of those B12 sources: no meat and no vegan supplement. You can call it a too restrictive, unhealthy vegan diet (because the diet doesn't contain meat), but you can equally call it a too restrictive, unhealthy omnivorous diet (because the diet doesn't contain vegan B12-sources). There is a kind of symmetry.

I'd say a healthy vegan diet is roughly as difficult as a healthy omnivorous diet, and a convenient vegan diet is roughly as easy as a convenient omnivorous diet.

Someone who is highly productive in reducing X-risks, is first highly intelligent, which means intelligent enough to know how to eat a healthy vegan diet, and second, most likely living in a wealthy environment with good access of healthy vegan food, which means able to follow the knowledge about healthy vegan diets. So that means if a person still has adverse health effects from the vegan diet, while following all knowledge about healthy vegan diets, it must be because of unknown reasons. And that seems very unlikely to me. We know so much about healthy food...