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Factory Farming: What Is It, and Why Is It Bad for Animals?

November 2, 2021

Imagine spending your entire life behind bars in a space not much bigger than your body. This is the stark reality for billions of animals who are imprisoned in factory farms around the world. As we will see, this broken system of food production has devastating consequences, not just for farmed animals, but also for people and the planet. 

What Is Factory Farming?

Factory farming is a system of raising fast-growing animals in extreme confinement, where animals’ movements are restricted, sometimes to the point where they cannot even turn around. Also known as concentrated animal feeding operations (CAFOs), this system of farming exists to meet the massive global demand for meat, fish, milk, and eggs. 

When Did Factory Farms Begin?

Tracing the history of factory farming is complex, but a major step toward intensive meat production started in the U.S. with the mechanization of pig slaughterhouses in the 1930s. 

Over the next few decades, the Green Revolution saw grains for animal feed become cheaper to produce thanks to new technologies such as genetic selection, chemical fertilizers, and pesticides, which made industrial animal agriculture more profitable. 

By the 1950s, the factory farming of chickens was commonplace, and since then policy decisions have helped to foster the continued growth of intensive animal farming.

What Happens in Factory Farming?

Animals ensnared in factory farming are treated like machines. Their only purpose in the eyes of the industry is to produce a profit, which leads to them being mistreated in a number of ways. 

Chickens Are Debeaked 

The stress of living in extreme confinement can cause chickens to injure and even kill each other with their beaks. Instead of giving these birds the space they need, the industry’s solution is to cut off or desensitize part of the beaks of young chicks, often with a hot blade. 

This amputation, referred to as debeaking, is known to cause severe pain. Chickens who are debeaked have difficulty carrying out everyday tasks such as eating and cleaning themselves. 

Cows and Pigs Are Tail-Docked 

Removing up to two-thirds of a cow’s tail is common practice in industrial beef and dairy production. The purpose is to prevent injury and disease that  are commonplace because of factory farming's cramped conditions, but tail-docking causes chronic pain and affects the cow’s ability to communicate. 

Piglets routinely have their tails amputated to prevent tail-biting, a behavior that is common in factory farms due to stress and overcrowding. The procedure causes acute pain and distress. 

Cruel Confinement

Extreme confinement is a defining feature of factory farms. Laying hens are often kept in battery cages, pregnant pigs in gestation crates, and young calves in veal crates. Even in places where cage systems are banned, animals are crammed into sheds in such high densities that they can barely move. 

Forced Molting

Forced molting is the practice of withholding food and water from laying hens to make them molt. A molt is when birds shed their feathers for new ones, and happens annually in the wild. Hens stop laying eggs during this time, but become more productive afterwards. Forced molting manipulates this natural cycle to save on feeding costs and increase egg production. 

Genetic Manipulation

Farmed animals have been selectively bred over time to make them more productive, often at great cost to their health and wellbeing.  Chickens raised for their meat are a prime example. 

In the 1920s, the average broiler chicken weighed just 2.5 pounds. The genetic selection of these birds for fast growth has increased the  average weight of a broiler to around 6.4 pounds. Today’s broiler chickens are so oversized that they suffer from heart problems and are often unable to walk. 

High Levels of Ammonia 

The vast amounts of feces and urine that are produced by thousands of animals lead to high concentrations of ammonia in the air both in and around factory farms. The colorless gas has a strong smell and irritates the eyes and lungs of both people and animals. 

Why Is Factory Farming Bad?

As outlined below, factory farming is not only bad for animals. It also has negative effects on the environment, the social fabric of farming communities, and the health of people worldwide.

Effects on Rural Communities 

As agriculture becomes increasingly industrialized and smaller, family-owned farms are forced out of business, rural communities see less local spending, lower family incomes, and higher rates of poverty. Not only that, but people who live near factory farms find that the noise of screaming animals, the noxious smell of waste lagoons, and the heavily polluted air affects their quality of life. Factory farms are disproportionately located in and around communities of color. 

Animal Welfare in and Outside Factory Farms

The American Veterinary Medical Association states: “An animal is in a good state of welfare if [he/she] is healthy, comfortable, well-nourished, safe, able to express innate behavior, and if [he/she] is not suffering from unpleasant states such as pain, fear, and distress.” As animals in factory farms live in cramped, unsanitary conditions and suffer constant pain, fear, and distress, they arguably do not have good welfare. 

Animals Suffer Violence

Some people would argue that meat production is always violent because it relies on the killing of sentient beings. Beyond this, countless undercover investigations by animal protection groups have revealed that animals trapped inside factory farms are routinely punched, kicked, beaten, dragged, and thrown. 

Antibiotic Resistance

There was a time when a paper cut could kill you if it got infected. Today, thanks to the discovery of antibiotics, most infections are easily cured. But we can’t take this for granted. By 2050, drug-resistant bacteria could kill 10 million people each year. 

Of all the antibiotics sold in the U.S., 65% go to animal agriculture. On factory farms, these are used preventatively to cover up for the unhealthy conditions that the animals are kept in. This misuse of medication creates resistant bacteria which can spread directly from live animals to people, be carried via meat, or be released into the environment through animal manure. 

Threats to Human Health

According to the Food and Agriculture Organization of the United Nations, "Livestock health is the weakest link in our global health chain.” 

As well as accelerating antibiotic resistance, factory farms create the perfect environment for viruses to emerge. “If you actually want to create global pandemics, then build factory farms,” writes Michael Greger in his book, Bird Flu: A Virus of Our Own Hatching. 

Keeping thousands of genetically similar farmed animals in close confinement makes it easy for emerging diseases to spread and mutate. The destruction of wild areas for intensive agriculture means that wild animals are more likely to come into contact with farmed animals and humans, further heightening the risk of zoonotic diseases spreading to people. 

Worker’s Health

Workers in factory farms spend several hours each day in close confinement with thousands of animals, many of whom are likely to be sick or dying. This is clearly not a healthy working environment, and exposes them to dangerous chemicals, bacteria, and zoonotic diseases.  

Inhaling dust and gases causes almost 60 percent of confinement workers in the pig industry to have chronic bronchitis, for example, a rate three times higher than that of other agriculture workers. Injuries are also common, especially in slaughterhouses, where incidents such as “hospitalisations, amputations or loss of an eye,” were recorded every second day between 2015 and 2017. 

Why Is Factory Farming Bad for the Environment?

Climate Change

Animal agriculture is responsible for 15.4% of global greenhouse gas emissions, roughly equivalent to emissions from the transportation sector. This 15.4% is composed of 26.3% methane, 50% carbon dioxide, and 23.7% nitrous oxide.

The primary carbon dioxide sources are fertilizer, equipment, transport, storage, and processing. The primary methane sources are animal belches and manure. The primary nitrous oxide sources are manure and fertilizer.

Air Pollution

A single factory farm can produce 1.6 million tons of animal manure each year, which is usually stored in a massive open-air cesspool. When this manure breaks down, it emits vapors and gases including ammonia, hydrogen sulfide, and methane. Of the 15,900 annual air pollution deaths related to agricultural food production, 80 percent are linked to animal agriculture

Land Usage

Animal agriculture uses 83 percent of global farmland but only produces 18 percent of calories and 37 percent of the world’s protein. Vast areas of forest are cleared to grow corn and soy to feed factory-farmed animals. 


Animal agriculture is one of the leading causes of global deforestation, and is linked to 75 percent deforestation in the Brazilian Amazon rainforest. Forests are decimated to grow corn and soy to feed farmed animals, and to graze cattle.

Water Pollution

The huge quantity of manure produced by factory farms, which is often contaminated with chemicals, heavy metals, and pathogens, is a major source of water pollution. When manure is applied to land as fertilizer in excessive amounts, nitrogen and phosphorus can leach into rivers and streams. Fertilizers used to grow corn and soy to feed farmed animals are another significant source of nitrogen and phosphorus. This causes algal blooms and kills fish, as has happened in the “dead zones” in the Gulf of Mexico and other coastal US waters.

How Are Animals Killed in Factory Farms?

Any animals considered unprofitable are killed and discarded long before they reach slaughter weight. Male chicks are routinely ground up alive, and weak piglets are slammed onto the ground.

At the time of slaughter, cows are shot, pigs are gassed, chickens are dipped into an electric water bath, and fish are skinned alive. The animals then have their throats slit and are taken apart on high-speed disassembly lines. 

Where Is Factory Farming Most Common?

By some estimates, the U.S. is home to 250,000 industrial livestock facilities. Factory farming is dominant in North Carolina, Iowa, Texas, Nebraska, Ohio, and many other states across the country. 

Factory Farming Facts and Statistics

  • An estimated 99 percent of farmed animals in the U.S. live in factory farms.
  • The most intensive factory farms are called Concentrated  Animal Feeding Operations (CAFOs).
  • A ban on factory farming is supported by 49 percent of adults in the U.S.
  • The crops we currently feed to farmed animals could feed an extra 4 billion people.
  • Farmed animals in the U.S. produce between 3 and 20 times as much raw waste as the human population.

Is Factory Farming Illegal?

Factory farming is currently perfectly legal in the U.S. and around the world. In the U.S. it is also largely unregulated. There are no federal laws to govern the standard of care for animals inside factory farms, and environmental regulations fall far short of providing strong and enforceable rules. 

Why Does This Still Happen?

The power and influence of big meat and dairy companies is a key factor in why factory farming still happens. The industry has long been using tactics such as political lobbying and misleading marketing to cover up for the harm it causes. Yet ultimately, factory farming exists because there is a high demand for cheap animal products. 

How Can We Stop Factory Farming?

One of the most useful things that we can do as consumers to help put a stop to factory farming is to swap meat, fish, milk, and eggs for plant-based alternatives. Every positive change you make to your diet takes us one step closer to a world without factory farms. 

To spread the word about factory farming and its devastating impacts, you can host an FFAC program at your school, institution, or workplace, and if you are a student, you can apply to join the FFAC Students Advocates program. Discover more ways you can take action here.

What Are the Alternatives to Factory Farming?

While regenerative agriculture is proposed as a solution, emerging research shows that these systems are not sustainable either. A plant-based food system may be the fairest, most sustainable alternative to the factory farming of animals. 


Cheap meat production comes at a high cost, especially to farmed animals, rural communities, and the natural world. The need to move away from factory farming and build a food system that is sustainable for our future has never been more urgent.