Analysis of Disability and Philanthropic Spending on Farmed Animals vs. Humans

Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Farmed animals are neglected, published by Vasco Grilo on June 24, 2024 on The Effective Altruism Forum.
Summary
Farmed cows and pigs account for a tiny fraction of the disability of the farmed animals I analysed.
The annual disability of farmed animals is much larger than that of humans, even under the arguably very optimistic assumption of all farmed animals having neutral lives.
The annual funding helping farmed animals is much smaller than that helping humans.
Introduction
I think one should decide on which areas and interventions to fund overwhelmingly based on (marginal) cost-effectiveness, as GiveWell does. Relatedly, I estimated corporate campaigns for chicken welfare, like the ones supported by The Humane League (THL), have a cost-effectiveness of 14.3 DALY/$, 1.44 k times that of GiveWell's top charities.
However, for communication purposes, I believe it is fine to look into the benefits of fully solving a problem as well as philanthropic spending. Animal Charity Evaluators (ACE) has a great graph highlighting the neglectedness of farmed animals in the United States relative to their scale.
In this post, I estimate the annual disability of and philanthropic spending on humans and farmed animals, both globally and in China[1]. The data and calculations are in this Sheet.
Methods
I got the annual disability of each group of farmed animals multiplying its population by its disability per living time in (human) years lived with disability (YLD) per animal-year[2], which I calculated from (1 - "welfare per time as a fraction of that of a fully healthy human as a fraction of the welfare range (normalised welfare per time)")*"welfare range". For a normalised welfare per time equal to:
0, corresponding to a neutral life, the disabilty per living time is equal to the welfare range, which makes sense. By definition, a dying human has a disability per living time of 1 YLD/year (which is equal to the welfare range of humans of 1), and a welfare per time of 0.
1, respecting a fully healthy farmed animal, the disability per living time is 0, which checks out. By definition, a fully healthy human has a disability per living time of 0, and it is natural to extend this to farmed animals.
In agreement with the above, disability throughout this post refers to the potential for increasing (
affective) welfare up to the level of a fully healthy being. In contrast, the global burden of disease study (
GBD) focuses on actual disability.
For simplicity, I did not consider years of life lost (
YLL). I would have to figure out the life expectancy as a function of age for farmed animals living in ideal conditions, as GBD
uses a reference life expectancy for ideal human conditions. A "reference life table, or theoretical minimum risk life table (TMRLT), is used in GBD to calculate years of life lost (YLLs) due to premature mortality. It was constructed based on the lowest observed age-specific mortality rates by location and sex across all estimation years from all locations with populations over 5 million in 2016".
I used Rethink Priorities' median welfare ranges. I relied on the value for pigs for cows, the mean between the values for carp and salmon for fish, and the value for black soldier flies for insects.
To find the normalised welfare per time of farmed broilers, hens and decapod shrimp, I assumed:
The time that farmed broilers, hens and decapod shrimp on ongrowing farms experience each of the 4 pain categories defined by the Welfare Footprint Project (WFP). I also supposed all broilers are in a conventional scenario, and that hens are in conventional cages or cage-free aviaries, using data from WFP to find the respective fractions.
Excruciating pain is 1 k times as bad as disabling pain[3].
Disabling pain is 100 times as bad as hurtful pain.
Hurtful pain is 10 times as bad as...