A few weeks ago, an open letter appeared calling on Effective Altruists to go beyond the cage-free campaigns and shift the focus from "welfare reforms" to promoting animal-free diets, especially in the wake of potentially very large amounts of funding flowing towards animal causes.
The original letter is here: https://beyondcagefree.org/ and an EA forum blog post by one of the organisers (@Anita Krajnc) can be found here. I also listened to Anita's interview in A Fork in the Road, by Vegan Report.
This is my humble attempt to write a reply, representing only my views as an effective altruist, but not others' and certainly not the EA community. The arguments of the letter, if I understand them correctly, are:
- Claim 1: Cage-free or welfare reforms have little or potentially even negative impact on other causes, including climate change and zoonotic diseases.
- Claim 2: As asserted in PETA's white paper on cage-free reforms, cage-free reforms make animal conditions "either marginally improved, unchanged, or, in some respects, even worsened".
- Claim 3: Total amount of animal suffering should not be the only variable, and we should also account for other moral theories (e.g. deontology or virtue ethics) as well as other metrics beyond suffering, such as animal rights.
This leads to the thesis that devoting most resources to cage-free campaigns is misguided, and we should shift some or most of the efforts to promoting plant-based diets. The three recommendations they give are:
- Broaden the Effective Altruism philosophy beyond utilitarianism and adopt a new impact metric focused on reducing the total number of animals bred into the food system.
- Develop an “Action Plan for a Plant-Based Future” that addresses both supply and demand (citing Meatless Mondays).
- Develop a High Ambition Coalition for Plant-Based Food Systems Transformation.
Let me try to address the claims, as I see them. Perhaps the weakest claim is the second: I believe PETA's white paper is a strawman of the evidence. This is Claude Opus 5.5 summary of the scientific evidence:
The letter cites PETA’s white paper to claim cage-free gains are marginal at best. The evidence does not support this.
- The EU’s scientific advisory body reviewed the evidence in 2023. It found cages severely restrict movement and natural behaviours, and recommended ending them to improve hen welfare (EFSA 2023).
- The most detailed quantification finds each aviary hen avoids at least 275 hours of disabling pain and 2,300 hours of hurtful pain versus a battery cage (Welfare Footprint).
- Higher cage-free mortality was a transition effect. In mature systems, it no longer differs (Schuck-Paim et al. 2021).
Cage-free hens do suffer more keel fractures, pecking injuries and dust exposure (CSES 2015). But the letter itself concedes cage-free lets hens nest, forage, turn around and spread their wings. Deprivation of these behaviors is the largest source of pain in cages. A list of harms is not a weighing of harms. When the harms are weighed, cage-free is clearly better.
Other AI systems seem to arrive at similar conclusions. I am not an expert myself, so it is hard to really gauge the evidence. Still, to the best of my ability, cage-free campaigns do significantly reduce suffering, all else being equal.
On the other hand, it seems that, indeed, cage-free is marginally worse for the environment, mostly because animals move more and thus spend more energy on things other than producing meat/eggs. However, Effective Altruists try to account for the scale of the problem. This means comparing the scale of animal suffering improvement against the scale of climate change worsening.
Since we already covered the animal welfare improvement side, let's now compare the climate change worsening: global equivalent CO2 emissions were 57.7 Gt CO₂e in 2024. Livestock emitted 6.2 Gt CO₂e in 2015, about 12% of the 50 to 52 Gt global total (FAO 2023; summary). Chickens account for 9% of livestock emissions. By product, meat is two-thirds, milk 30%, and eggs the rest (same FAO report). So eggs emit roughly 0.21 Gt CO₂e (~= 6.2 * (1-2/3-0.3)), about 0.5% of global emissions. Chickens overall are0.56 Gt CO₂e.
Eggs cause about 0.2 Gt CO₂e per year, roughly 0.4% of global emissions. Estimates of the extra emissions from going cage-free range from none (Pelletier 2017) to about 20% per kg (Leinonen et al. 2012; Dekker et al. 2011). Fully organic production would double emissions (Martinic et al. 2026). However, cage-free campaigns target barn and aviary systems, not organic. Even a full global switch would add under 0.1% to global emissions. Part of global production is already cage-free, so a realistic figure is closer to 0.05%.
The other large group of caged animals is breeding sows, kept in gestation and farrowing crates. Pigs cause 14% of livestock emissions, about 0.9 Gt CO₂e or 1.7% of the global total (FAO 2023). Crate bans only change how sows are housed. The fattening herd causes most pig emissions and is unaffected (Thoma et al. 2018). One life-cycle study modelled US farms moving sows from gestation stalls to group pens (Bandekar 2015). Sows in pens needed slightly less feed. Pens also needed about 65% more barn space, which partly offset that gain. The net result was about 1% lower emissions per kg of pig. However, only 58–60% of the model’s uncertainty simulations showed a reduction, so one could argue that the result is indistinguishable from 0. On the other hand, we found no comparable study for farrowing crates. Free-farrowing pens need more space and can raise piglet mortality, so a small increase is plausible. If crate-free housing changes pig emissions by 0–5%, the global effect is at most 0.08%. Together, moving all caged animals to cage-free would likely add under 0.2% to global emissions.
Climate impact is not just CO₂ emissions. However, CO₂e emissions might easily be the most important environmental impact. Additionally, historically the EA community has placed greater emphasis on animal welfare than on climate change EA Survey 2024, and for what it is worth, I agree with that prioritisation. I think it is a good testament to the EA community to have almost always placed animal welfare among the top 3 causes even when climate change has been more popular among the general public.
Perhaps the largest uncertainty is the impact on wild animal welfare. One could consider second-order effects on soil nematode wildlife, which, taken seriously, would violently swing the estimates of whether cage-free is indeed good or bad; see @Vasco Grillo's posts. However, it contains a lot of uncertainty and has a stronger dependence on fully embracing utilitarianism, which gives pause to many, including myself. The impact on vertebrate wildlife has also been discussed in this forum but seems hard to settle. My key takeaway is that, if we do not account for potential displacement of wild animals whose life net-positivity might be hard to ascertain, the climate impact of cage-free transitions is tiny on the large scale of things (which is good!).
On disease and use of antibiotics, the evidence of cages is mixed. A common assumption is that cage-free hens live outdoors, but most campaigns target barns and aviaries, where hens stay indoors. The main increase in pandemic risk comes from contact with wild birds. In the Netherlands, free-range farms were 6.3 times more likely to catch low-pathogenic bird flu than indoor farms (Bouwstra et al. 2017, cited in Gonzales et al. 2021). Indoor cage-free systems have their own trade-offs. Hens living on litter are in closer contact with their droppings. They get more parasites and bacterial infections, and more of them die (Lay et al. 2011). A survey of 405 German farms found that caged flocks needed fewer veterinary treatments, including antibiotics (Kreienbrock et al. 2007). But cages have problems too. In an EU survey of 3,768 flocks, caged hens were about five times more likely to carry Salmonella (Van Hoorebeke et al. 2010). Antibiotic resistance showed no clear link to housing type (Van Hoorebeke et al. 2011).
Cost is the final side effect highlighted in the letter that I think is worth discussing here. Cage-free eggs are more expensive to produce. Barn eggs cost about 17% more in the EU (Majewski et al. 2024). A US trial found 30–40% more (UC Davis). However, this cuts both ways again: it will make food less affordable in poor countries, but higher prices should also mechanically reduce the amount of eggs consumed, although not by much: a 10% price rise cuts consumption by roughly 3% (Andreyeva et al. 2010). If the full 17% cost increase reached shoppers, egg consumption would fall by about 5%.
Further, I think an often-overlooked impact of cage-free campaigns is that they might be shifting public views on animal welfare. The "End the cage age" campaign in Europe and Proposition 12 in California, for example, have created some public recognition that animals matter. By getting people to sign the petition, opinions might be changing and shifting in the direction that animals are sentient beings. This strategy could eventually create the same public consensus that currently exists on climate change, and lead to legal bans (Shapiro and Siu). This consensus seems rather necessary if we want to end factory farming, and signing a petition often feels a lot easier than going vegan. In other words: politically oriented cage-free campaigns might be inadvertently leveraging the foot-in-the-door strategy often advocated for by Tobias Lenaert; see How to create a vegan world.
Now, with respect to the focus on utilitarianism, I think the claim is a bit too strong. Effective altruists indeed tend to place significant emphasis on utilitarianism, among other things, because historically it has been more prescient in moral matters than alternative theories. However, Effective Altruism has also championed the idea of moral uncertainty, and Rethink Priorities has a moral parliament tool that allows many in the community to account for more than basic utilitarianism. This, unfortunately, does not necessarily give clear, settled answers. Perhaps the claim by the Beyond Cage Free campaign supporters is that it's not just animal suffering that matters, but also animal rights, and that animals do not deserve to be killed. For what it's worth, I think that is true, and many Effective Altruists would agree. I would love to see the end of factory farming, and let animals live nice lives.
However, the biggest disagreement is not about utilitarianism, but about tractability: if there were clear ways to effectively promote plant-based diets, the Effective Altruism community would likely be highly supportive of it. For example, there is an ongoing debate in the community about the extent to which alternative proteins could be such a candidate (here, here). So tractability is, in my humble opinion, the actual crux; if animal liberation advocates proved there were tractable ways of promoting plant-based diets, it would change many opinions. There is some pessimism that this is even possible, and the reason why cage-free campaigns have been a well-funded intervention: because at least here, we can get partial wins (all things accounted for). However, I (and I guess many in the EA community) would be excited to learn effective ways to promote plant-based diets, so please let us know if you find any!
Disclaimer: please note this only represents my views, not those of the EA community or my employer. I'd like to make this point super clear.
