We are all just animals. Why animal health is public health too

The vision of the Harvard T.H. Chan School of Public Health is bold - Health, Dignity, and Justice for every human. What's conspicuous in its absence is not unique to Harvard. Public health curricula across the United States fail to adequately discuss and debate the value of animal suffering.

As of today, there are around 8 billion of us. While much has been written about how our populations change, inequities in health outcomes across the world, and existential concerns that we collectively face, there's another number I want to draw your attention to: 100 billion. 100 billion animals are killed for meat and other animal products every year. At any given point, factory farms house 23 billion animals.  What we know of factory farms is often harrowing accounts of how these animals are treated.

An excerpt from an HSUS report¹ about how chickens are raised in factory farms in the United States states: "The birds are hastily caught and can suffer dislocated and broken hips, legs, and wings, as well as internal haemorrhages during the process. The birds are put into crates stacked one atop another on trucks. During their journey to slaughter, they are not given any food or water and are afforded little if any protection from extreme temperatures."

This isn't an exaggerated account meant to evoke sympathy - this is an accurate description of what happens in an industrial farm, an accurate description of processes involved in how our food makes it to the plate. This is public health. Most students of public health would agree that this is worth talking about. Yet, in my year and a half of public health education, I’ve yet to encounter a single classroom discussion on our approach to animal welfare in driving health agendas for the population. This vacuum shows up in a few different ways. 

First is simply an abject lack of any teaching on what we know about animal welfare and policy in the school. I took a closer look at the Master of Public Health in Nutrition program at HSPH, a program that I figured was the most likely to talk about animal welfare in food systems. Unfortunately, I learned very little. If you take a look at any of the required courses or the field of study requirements for the nutrition program, there isn’t a single discussion about the role of factory farms in our food systems, and the mass-scale suffering we subject sentient beings to. None of the department’s required or field-of-study courses - covering biochemical nutrition, public health nutrition, evaluation, translation, and research methods - mention animal ethics, livestock welfare, or humane agriculture in their syllabi.

Unfortunately, this criticism applies to every department at the school, and the broader Harvard community. Apart from nutritional implications of food, factory farms have major implications for social determinants of health and public policy. Factory farms and meatpacking plants rely on low-wage, racialized, and often migrant labor. Workers, many of them undocumented or from marginalized communities, endure dangerous, high-speed, repetitive tasks that lead to amputations, respiratory problems, and chronic pain.² Studies have shown rates of injury and illness in meatpacking plants several times times the national average. COVID-19 made this visible: outbreaks in U.S. meatpacking plants infected tens of thousands, revealing how economic precarity and immigration status prevent workers from speaking out or staying home sick.⁵ Crowded animal conditions foster antibiotic resistance and zoonotic disease emergence, but those health risks fall unevenly.  Thus, animal cruelty and human inequity are obviously co-produced by the same systems. These are worthy discussions to have in our classrooms as we discuss health and social policy. It’s disappointing that this isn’t the norm.

One of the few notable programs that engage with these conversations is the Brooks McCormick Jr. Animal Law & Policy Program at the Harvard Law School that leads teaching, litigation and policy research into issues of animal advocacy. The centre also runs reading and writing groups that highlight the role of animal welfare in our relationship to health, environment, climate change and infectious diseases. 

A second key gap is in how we engage in public health research. We exclude animal welfare as a critical metric from our research frameworks. When public health researchers evaluate food systems or climate policies, they meticulously track carbon emissions, land use efficiency, water consumption, and human nutritional outcomes, yet systematically exclude animal welfare metrics⁴. This creates a fundamental gap in our understanding. A comprehensive evaluation of our food system requires quantifying animal welfare, risks of zoonotic diseases, and patterns of antibiotic use alongside environmental impacts, especially when evidence shows that these often move together. 

A common argument made here is that most carbon emission metrics already capture the impact of industrialised farming. But that assumption is flawed. Climate and diet models, whether life-cycle assessments or “sustainable diet” frameworks, consistently rate poultry and aquaculture as climate-efficient because they convert feed into meat quickly. As Rydhmer and Roos⁴ show, that efficiency depends on conditions that are often worse for animals. Confinement, overcrowding, and selective breeding for rapid growth, all of which drive down emissions are also driving up suffering. The same blind spot appears in nutrition and food-security research, which often celebrates industrial poultry and fish as affordable protein sources for low-income populations. We obviously have a model of “protein security” that improves calories per dollar but normalises cruelty as efficiency.

I learned the most about this tension from Hannah Ritchie’s writing. She reminds us that what’s good for the planet is not always good for the animal - and that these goals often pull in opposite directions.³ Choices that reduce environmental impact can worsen animal welfare, and vice versa. Larger animals like cows or pigs have a higher carbon footprint but yield much more meat per life; smaller animals like chickens or fish have a lower footprint but are killed in vastly greater numbers and often endure worse conditions. The most climate-friendly systems are not always the most humane. I don’t mean to say that caring about the climate and caring about animals are incompatible goals. It’s possible to pursue both. But doing so requires measuring both independently. We need to know the suffering that’s part of the equation to see the trade-offs clearly.⁷ 

Finally, moving past my consequentialist arguments, I want to make the plea that our ethical frameworks contain a fundamental inconsistency: While One-Health approaches talk about the interconnectedness of environmental health with human & animal health, these conversations continue to treat animal health as necessary, primarily as a tool to keep humans safe. In the public health curriculum, the closest thing to a discussion of animal welfare appears in a Planetary Health course, where livestock systems, wildlife loss, and zoonotic spillover are examined through ecological and epidemiological lenses. While this is a valuable start, I want to point out that these arguments are not ethical concerns about animal well-being.

And I understand why. If it were my role to persuade public health schools to actively consider including animal suffering and animal welfare in their curricula, I would make arguments for how animal suffering is directly linked to human suffering. The climate impacts are undeniable. There’s huge implications for deforestation and biodiversity loss. For my colleagues in the infectious diseases line of work, I would talk about pandemic risks and antibiotic resistance. For my own friends working on issues of labor, housing and antiracism initiatives, I would discuss dietary colonialism, work exploitation and occupational health.

The harder argument to make is that we have an ethical responsibility to reduce suffering when we have the means to do so. What is missing from most public health debates is an animal rights lens. If we treated animal welfare as an extension of animal rights, we would have to think beyond questions of efficiency or human benefit. Animal rights are moral, not legal; they are grounded in ethics and experience rather than codified protection. The animal rights view holds that some things should never be done to animals, even if they serve human interests.⁶ We can also make the case for animal rights that does not rest only on reducing pain but on recognising the moral significance of the animal itself. If an animal is capable of suffering, then that suffering counts, regardless of its market value or social function. Yet our systems continue to treat animals as means to an end. They are valued for their economic contribution or protective functions, but not for their capacity to experience the world. 

Despite progress in other fields, including those of equity and justice, the treatment of animals has not improved. Factory farming remains the norm in wealthy countries, and meat consumption rises with income. This is not a moral indictment of individuals but a reminder that reducing suffering, and I use the term suffering broadly, is central to the mission of public health. Progress isn’t guaranteed; it is continuously worked upon. Students graduating with public health and public policy degrees enter the field with sophisticated understanding of human health disparities, environmental determinants, and policy implications, yet most leave without ever critically examining one of the largest sources of suffering and threats to future pandemics on the planet. This represents not just an ethical oversight but a scientific inconsistency that undermines the field's commitment to evidence and ethics.

Credits to Karishma Swarup for the title

References: 

1. The Humane Society of the United States, "An HSUS Report: The Impact of Industrialized Animal Agriculture on Rural Communities" (2008). Impact of Animal Agriculture. https://www.wellbeingintlstudiesrepository.org/hsus_reps_environment_and_human_health/7
2. Sky Chadde, “COVID-19 Cases, Deaths in Meatpacking Industry Were Much Higher Than Previously Known, Congressional Investigation Shows,” Investigate Midwest, October 28, 2021, https://investigatemidwest.org/2021/10/28/covid-19-cases-deaths-in-meatpacking-industry-were-much-higher-than-previously-known-congressional-investigation-shows/.
3. Hannah Ritchie, “What Are the Trade-offs Between Animal Welfare and the Environmental Impact of Meat?” Our World in Data, June 10, 2024, https://ourworldindata.org/what-are-the-trade-offs-between-animal-welfare-and-the-environmental-impact-of-meat.
4. Lotta Rydhmer and Elin Roös, “Advancing Metrics for Animal Welfare and Antibiotic Use in Sustainability Assessments of Diets,” Sustainable Production and Consumption 59 (2025): 288–304, https://doi.org/10.1016/j.spc.2025.08.020
5. Human Rights Watch, “When We’re Dead and Buried, Our Bones Will Keep Hurting:” Workers’ Rights Under Threat in US Meat and Poultry Plants (September 2019), https://www.hrw.org/report/2019/09/04/when-were-dead-and-buried-our-bones-will-keep-hurting/workers-rights-under-threat.
6. Kriegel, Uriah (2013). Animal Rights: A Non‐Consequentialist Approach. In K. Petrus & M. Wild, Animal Minds and Animal Morals.
7. Elsbeth K. Paige-Jeffers, “Animal Welfare: Measuring Strategies for Improving Lives” (MA thesis, University of Southern Maine, 2017), https://digitalcommons.usm.maine.edu/etd/310/.