The US produces and consumes more meat, dairy, and eggs per person than any other country in the world, almost all of which comes from animal feeding operations, which are most commonly known as factory farms.
There are around 25,000 factory farms in this country housing around 1.6 billion animals at any given time, mainly chickens, pigs, and cows. These sentient animals are treated like widgets, crammed in so tightly they can barely move in squalid conditions that induce sickness and stress for the entirety (or for beef cows the last quarter) of their short lives before they are killed and sent on to the next stage of the assembly line. And the human workers in this supply chain face incredible exploitation and danger, physically and psychologically.
Approximately 40% of US corn and 70% of US soy goes toward feeding livestock, along with a mixture of various grains. Consequently, factory farming is fundamentally intertwined with industrial crop agriculture and all the problems endemic to it like soil degradation, massive pesticide and chemical fertilizer usage, and biodiversity loss. And in developing countries like Brazil, animal agriculture is a major source of deforestation (for cattle ranching or growing soy for feed).

Factory farming is one of the most awful things ever created by humans; the case against it is well-documented and objectively airtight. The horrific downsides are numerous and severe, including public health damage from multiple directions, significant contributions to most varieties of ecological crisis and environmental injustice, and animal torture on an incomprehensible scale. Factory farms produce devastating air, land, and water pollution; massive greenhouse gas emissions; antibiotic-resistant bacteria; and diseases (you could hardly design a better petri dish for creating new pathogens).
Nevertheless, there is little political will to dismantle or even meaningfully regulate factory farming in most places as regulatory capture reigns supreme. Republicans are broadly supportive and protective of the industry at all levels of government, and many Democrats to a lesser extent are as well. For example, methane digesters—alongside carbon markets—were the centerpiece of Biden’s agriculture policy platform and his administration is following through with significant support (as are many state governments). These machines capture methane emissions from the huge feces lagoons produced by factory farms to be piped away and sold as biogas energy, effectively acting as factory farm subsidies. And the $1.5 trillion annual spending bill that Congress just passed contains two riders that further protect factory farming from regulation of its copious air and greenhouse gas pollution.
Eliminating factory farming in the US would certainly face fierce resistance from the large and powerful business interests that profit off of it. California passed a ballot measure requiring animals to have just a little bit more room to move around, and the industry has been throwing everything they can to stop it because even such a small reform would slash their profits. It would also likely face resistance from many consumers, as meat has become a core part of US culture and conservative identity politics in particular. But I do not think having access to unlimited cheap meat, eggs, and dairy products is a deeply held requirement for most people in the US. The popularity of more expensive, ostensibly more sustainably raised animal products and plant-based substitutes are on the rise, and there is a reason that the industry fights so hard to criminalize documentation of the horrors that take place behind its closed doors via ag-gag laws.
While I cannot comprehensively plot out precisely what our just and sustainable food system will look like yet, I think any sober analysis leads to the conclusion that the US will need to produce and consume a smaller quantity of animal products. Some imagine universal veganism, perhaps with lab-grown meat; some imagine the replacement of factory farms with pastured, humanely raised livestock; and others imagine some sort of mixture of these two.
There are serious issues with scaling up lab-grown meat, so it should not be counted on, but research will certainly continue and we will see what happens. Many of the problems with existing efforts at regenerative animal farming in the US are at least in part due to the profit motive. There are many examples of small-scale and more sustainable livestock rearing throughout the world—like silvopasture and Indigenous pastoralism—and an agroecological system will require integrating animals with crops in order to replace fossil fuel energy and chemical fertilizers. I do not think they would necessarily need to be raised for meat production, although this highlights opportunities for more ecological and humane production of smaller quantities of eggs and dairy.
The morality of sustainably raising animals for food—particularly in places where it is not necessary for subsistence—is complex and beyond the scope of this article. But no matter where you stand, everyone can agree that factory farming is abhorrent and has to go. We need a broad movement fighting on all different scales to shut down factory farms and regulate them out of existence while building up an alternative agroecological system that provides food sovereignty, ecological stability, and flourishing for human and nonhuman life on this planet.