Thanks Nick. I'm really glad to see that Cynthia Shuck of the Welfare Footprint Project has just commented around the specifics on cage-free, so I'll defer to her on that. I'll just add a few quick thoughts on your comments here.

"If there had been 50 studies which compared mortality between two global health intervention and overall results was unequivocal, we would probably conclude that there was no major difference between the two ... Mortality in hens seems pretty easy and likely inexpensive to measure."

• To clarify: the results are not unequivocal. Different studies point to very different results. This is both due to study design, but also due to lots of variation in actual conditions (lab vs on-farm, small farms vs. big farms, experienced farmers vs. inexperienced, healthy pullets vs. unhealthy, etc).
• Mortality on-farm is indeed easy and cheap to measure, but very few farmers will allow researchers on-farm to measure this or publicly share their own results. So a lot of these studies end up being in unrepresentative lab conditions or on individual farms that may not be representative.
• That said, I think the on-farm data that Cynthia cites (the "database from a breeder for countries around the world") is probably the best data we have. And it does indeed conclude there isn't a major difference between the two systems.

"Before this post I thought it was super obvious that cage free was way better and it was just a magnitude-of-good question. After this post, I would appreciate a post on the forum actually laying out why there is a "high likelihood of cage free bring robustly net positive"."

• I don't think this post should be a major update for you on whether cage-free is better than caged. It's just not clear that mortality is that good a proxy for total welfare. E.g. everyone agrees that mortality is highest in free-range and pasture-based farming, but few conclude from that that these systems are worse for total welfare than intensive confinement.
• Given how hard it is to measure animals' actual subjective wellbeing, I think we should look to lots of different sources of evidence and reasoning, not just the few indicators we can objectively measure. My personal view that cage-free is better is probably based on something like: ~40% priors that pretty much all animals like to move around and have more space, ~30% preference studies showing that hens really value the things they can only access in cage-free (nesting boxes, perches, dustbathing, etc), ~10% my sense that pretty much all independent animal welfare scientists agree it's better, ~10% my experience with rescued battery cage hens who have a very strong preference to stay out of cages, ~10% that mortality is pretty much the only indicator suggesting it could be worse and actually that data is very messy. (TBC: not an official CG view, and it's possible I'd change those numbers a bunch on reflection. I share them just to suggest that resolving the mortality debate wouldn't be transformative for my views.)

Thanks for writing this post! Thanks too for sharing it in advance, and sorry I didn't have time to review it. For the same reason, I won't have time now to go into the detail that I'd love to on your specific claims. (It's great to see such a vibrant discussion in the comments! I'd love to see more critical discussion of the evidence like this in the EA animal welfare space.) So I just wanted to share three high-level reflections.

First, I agree with you on the need for more evidence collection on the animal welfare outcomes of popular interventions. We've funded >$20M of such evidence collection work (e.g. the Welfare Footprint Institute, Rethink Priority's review of evidence across multiple areas, the shrimp slaughter study you cite, a Guelph study on broiler genetics welfare outcomes, and a dozen other studies and meta-analyses). We've also done a ton of internal analysis on this, e.g. we have a complicated model of estimated rates of factory farm meat displaced by alt protein in various scenarios. And yet we need to do a lot more! I'm really excited that the likely inflow of more animal welfare funding will enable a lot more high-quality evidence generation. And I completely agree we should prioritize it.

Second, I think we need to be realistic about how much certainty that evidence collection will create -- and how quickly. I think your cage-free example is a good one. There have been 50+ studies and large-scale data collection efforts on relative mortality in caged vs. cage-free housing systems and we still don't have a clear answer on it. And yet mortality is just one of 20+ metrics we could look to as partial proxies for what we really care about: "what is the relative overall welfare of caged vs. cage-free birds?" I think we should also fund studies and commercial data collection on all those other metrics (or at least the ones current tech allows us to measure). But that will take many years and, even then, people will reasonably debate the relevant importance of each of those 20+ metrics to the welfare of birds. 

(I should note that I really admire the work you're doing to try to significantly accelerate the pace of this kind of research, starting with shrimp slaughter. I think I agree with you on everything you think should be funded to accelerate it further, and am confident we will fund that full agenda -- please tell me if there's something we're not covering. And I hope that advances in AI can accelerate the evaluation and syntheses of existing evidence too.)

Third, I think we need to continue to act to alleviate suffering even in the face of significant uncertainty. I'm jealous of global health direct service provision (e.g. anti-malarial bednets, cash payments) where I think you can have perhaps the closest to total certainty of positive impact of any areas. But I think for basically any advocacy intervention in EA (whether in AI safety, bio, farm animal welfare, or even global aid advocacy) you have to accept significant uncertainty not just about the immediate impacts but also about second, third, etc. order effects. That's not an excuse for ignoring the uncertainty. But I think when a cluster of evidence points to a high likelihood that something is robustly net positive -- as I believe it does for cage-free (sorry I don't have time to go into all the specifics here!) -- than we should move forward on it. I think the opportunity costs of waiting for a higher confidence level of evidence are too high.

Thanks again for writing this! One of the things I love most about EA is the application of critical thinking and evidence to disrupt commonly accepted wisdom, and I think this is a good example of this. I disagree on some of the specifics -- wish I had the time to explain more -- but I'm really glad you wrote and published this.

I'm afraid I can't think of much beyond publicizing this effort and its importance

I agree that's the best solution, but I think it's unfortunately much less tractable in most places than corporate campaigns. In the one large producer where it is right now, the EU, we're investing heavily in legislative work. 

Thanks! Claude deserves all the credit for the charts :)

I'm not wild about this campaign either. I've shared this feedback privately with Aidan and Thom, but think there's value to doing so publicly to make clear that EA / the animal movement's moderate wing / FarmKind's funders don't uniformly endorse this approach. (To be clear: I'm writing in my personal capacity and haven't discussed the following with anyone else at Coefficient Giving.)

I'm a huge fan of FarmKind's team. I've personally donated to them and directed funding to them via Coefficient Giving. I thought they did an incredible job during the Dwarkesh fundraiser earlier this year and I admire their ingenuity and grit in pursuing the very hard challenge of bringing in counterfactually new funds to effective animal advocacy. I appreciate that they meant well with this campaign, which I think they saw as using a a playful fake-feud with Veganuary to generate media.

But I thing this campaign was a mistake for three reasons: 

1. This feels like an incitement to infighting, which has long plagued the animal movement. In recent years, I've seen the abolitionist / more radical wing of the animal movement take major good faith steps to reduce this infighting (see, e.g., my session with Wayne Hsiung at this year's AVA). Whether Veganuary was in on this or not, I'm seeing vegan activists reasonably interpreting this as an attack on their advocacy. I think we should have a very high bar for deliberately starting a fight in the movement, and I don't think this meets it.
2. This feels like an attack on vegans. I think we should also have a very high bar for attacking well-meaning people doing good in the world, whether vegans, EAs, organ donors, aid workers, or longtermists. I appreciate that attacking vegans wasn't the campaign's intent, but I think it was the predictable result, and certainly how the folks in the Daily Mail's comments sections have (gleefully) interpreted it.
3. This feels dishonest. To be clear: I don't think FarmKind intended it this way and I think the people behind it are deeply ethical people. But I think our movement is at its best when we hold ourselves to high standards and that includes not deliberately misleading people. And creating a fake "meat-eating campaign" feels like it crosses the line for me.

Again, this isn't to question the intent or abilities of FarmKind's team. Instead, I'm sharing how I personally feel about this campaign. I hope we can avoid campaigns like this in future, while continuing to pursue the innovation in tactics that the animal movement and EA needs. 

Thanks David! That's very kind of you :) And TBC: I wouldn't have skipped the whole newsletter -- just weighing on ideal protein consumption, which was a bit of a digression from the main point. (And I had actually considered just saying something like "I don't know how much protein you should eat, but it doesn't matter because we can't influence it much.")

Totally fair feedback. I agree that I should probably have just argued that the general concept of UPFs is nonsense. My sense is that most of the evidence for the harms of UPFs is correlational and based on studies that look at high consumption of fast food and other junk food that we know is based for you based on high sugar, salt, and caloric levels. (I.e. where you don't need to add UPF to explain why they'd be unhealthy.)

My sense is also that the evidence for food additives like emulsifiers, stabilizers, colorings, and artificial sweeteners posing health risks is surprisingly weak given the public uproar. And while I agree that chicken doesn't contain those things, chicken feed typically contains a whole different set of things that would scare people if they had to disclose them, like antibiotics, animal by-products, and lots of artificial ingredients to make up for nutritional deficiencies from a corn/soy-based diet. (Though, to be clear, I think the evidence that those feed additives pose direct health risks is also weak, with the possible exception of antibiotics contributing to antibiotic-resistant Salmonella.)

Thanks David. Yeah I agree that something closer to 1.6 gram per kilogram is probably ideal for gaining muscle mass, per what your ChatGPT answers say. But my guess is that most Americans aren't doing the required weights to actually gain muscle mass. And my guess would be that caloric restriction / GLP-1s are surer ways to loss weight. But I'm also far from an expert on any of this, so on reflection I should have just skipped weighing in on this point at all.

Only a relatively smaller number of breeding hens laying ~275 eggs each per year