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What is factory farming and why is it a problem?

We often think of the UK having small local farms with frolicking lambs in fields. In fact, over 70% of animals are raised on factory farms.

Factory farms are associated with poor animal welfare and high environmental costs.

What is factory farming?

Factory farming is an intensive form of industrial agriculture focused on massive meat, fish and dairy production. Animals are reared year round in huge numbers. They are bred to grow quickly and many are fed on mono-cropped grain instead of their traditional diet.

Factory farms are focused on generating profits. But they’re associated with many animal welfare and environmental costs, which we explore below. Factory farmed animals are kept inside, in large numbers and forced through a life cycle designed for human consumption. Factory farmed fish are kept in incredibly high densities in small nets or containers, either in sheds on land or in the ocean.

Factory farms can be enormous in scale, and they are on the rise in the UK. In 2017, the Guardian reported that there were 800 mega farms for animals – a 26% rise in intensive factory farming in six years. These farms have warehouses with more than 40,000 birds, 2,000 pigs or 750 breeding sows. In the UK, over 70% of animals are raised on factory farms.

What are the problems with factory farming?

Factory farming and animal rights abuses

Peta says, “Factory farming treats animals as though they are meat factories rather than sentient beings. Animals are selectively bred and genetically manipulated to gain weight quickly or to produce more eggs or milk than their bodies would naturally. They are crammed into cages and pens so small that they can barely move. Their food, lighting and breeding cycles are regulated in line with productivity. Most, if not all, of their natural instincts are denied.”

Animals in these systems also face mutilations, forced impregnation and separation from their offspring. We explore these issues further in our article on animal rights and animal welfare in the food industry.

Factory farming and climate change

In 2006, the UN’s FAO stated:

“Factory farming endangers the survival of other animals and plants, with impacts including pollution, deforestation and climate change.”

The animal farming industry is responsible for almost 56% of greenhouse gas emissions from our food. Yet it provides just 37% of our protein and 18% of our calories.

There are two big sources of emissions from the animals we eat. Cows and sheep burp large amounts of methane during the torturous process of digesting grass. Methane is a very powerful greenhouse gas.

Animals also require a large amount of land, both to live on and for their feed. This demand for land can result in massive deforestation, including of the Amazon: in fact, it’s the biggest single cause of deforestation globally.

In 2021, a study found that the majority of the world’s cropland was being used to feed livestock, rather than people. This is incredibly inefficient. The most straight-forward way to understand this is by thinking about a cow being fed. If a cow eats a meal of soya, they won’t save up all the energy for our steak or milk: they’ll use some of it up by walking around, mooing or just generally being alive. If we’d eaten that soya directly, we’d have received much more energy compared to the emissions from growing it.

In fact, a farmed cow will eat somewhere between sixteen and twenty five times the weight of crops that it will ‘give’ in the form of meat.

By a very conservative estimate, someone who eats a large amount of meat will therefore have two and a half times the dietary carbon footprint of a vegan. These figures don’t even account for all the things we could be doing with land currently used for animals if it were freed up – like storing carbon.

Read our feature on the climate impacts of meat, vegetarian and vegan diets for more on this.

Does factory farming have a higher carbon impact than other animal farming?

If comparing calorie for calorie, factory farming can have a similar or sometimes lower carbon impact than other ways of animal farming, because it rears animals so quickly and requires less land.

In 2020, a study compared the greenhouse gas emissions from organic and non-organic meat. It found that emissions were largely equivalent. While emissions from non-organic meat came from methane burping and feed, organic animals were found to generally grow slower, live longer and therefore have higher emissions before being slaughtered.

In August 2022, George Monbiot argued that the world’s worst farm products when it came to the environment were in fact organic, pasture-fed beef and lamb. He wrote,

“Perhaps the most important of all environmental issues is land use…. Arable crops, some of which are fed to farm animals, occupy 12% of the planet’s land surface. But far more land (28%) is used for grazing: in other words, for pasture-fed meat and milk. Yet, across this vast area, farm animals that are entirely pasture-fed produce just 1% of the world’s protein.”

Nonetheless factory farming holds a big responsibility for our unsustainable approach to producing and consuming meat. Factory farming isn’t geared towards using less land so that we can save it for nature: it’s geared towards farming more animals so we can eat more meat and dairy for its profits. Arguably, this is the key climate problem – the sheer quantity of animal products we consume.

Factory farming and biodiversity loss

Carbon is not the only environmental issue associated with meat, dairy and fish consumption. Many of the impacts discussed above also come at a high cost for biodiversity and natural ecosystems. 

Converting land for grazing or feed destroys natural habitats. In 2019, a study found, “At least 200 species of large animals are decreasing in number and more than 150 are under threat of extinction… [and] humans' meat consumption habits are primarily to blame.” The Amazon rainforest, in particular, is under threat. Huge areas are being deforested or burned to grow soya – 90% of which is fed to animals.

Likewise, trawling for fish and fish feed destroys the seafloor, jeopardising the homes of other sea life. 

As with carbon emissions, non-intensive animal farming may have as much or more of an impact when it comes to biodiversity loss, due to the large amounts of land required. Nonetheless, factory farming has a significant role to play in its unsustainable use of feed and the way that it drives increased meat and dairy consumption. 

Rear view of tractor spreading manure on field
Manure being applied to fields.

Factory farming and water pollution

Animal farming also causes widespread pollution.

In 2017, the Guardian and Bureau of Investigative Journalism reported, “Serious pollution incidents in the UK from livestock farms are now a weekly occurrence, leading to damage to wildlife, fish, farm livestock and air and water pollution.” The common offender was said to be slurry from dairy farms.

Factory farming is the prime culprit of pollution from animal farms. Factory farms house huge numbers of animals. This means that manure builds up in large quantities. EarthJustice reports,

“An average dairy cow, for example, produces well over 100 pounds of manure a day – more than 200 times what an average human produces. A facility with hundreds or thousands of cows can produce the same amount of waste as an entire town, or even a large city.”

In the US, this waste can be stored in huge, open-air lagoons, often as big as several football fields. Slurry and manure stores can leak. Liquid manure is then often sprayed on crops. But sometimes too much is applied to avoid the high cost of transporting the manure off site, or the plants just cannot absorb all the nutrients, meaning that it runs off into waterways.

This can cause eutrophication – where the excess nutrients cause massive growth in aquatic plants and algae, absorbing all the available oxygen. The impact from this might be familiar to those living in the south of England and Wales, where the River Wye is facing collapse due to pollution from local industrial chicken farms. At its most extreme, such pollution can lead to dead zones – biological deserts home to almost no life. In 2017, an investigation by Mighty Earth identified industrial meat production as a key cause of one of the largest dead zones ever recorded, in the Gulf of Mexico.

Factory farming and air pollution

In 2019, the Bureau of Investigative Journalism also investigated ammonia pollution from UK dairy farms – a contributor to the UK’s air pollution crisis.

They conducted tests around eight dairies in the UK (including six intensive dairy units that housed more than 700 cows and a conventional farm that allowed grazing). Ammonia hotspots were found at two of the intensive dairies and in specific locations around the outdoor farm.

Ammonia (NH3) gas is the only pollutant on the rise in the UK, and its key source (about 65%) is from livestock farms – particularly from slurry (a mixture of faeces and urine). NH3 is released when slurry is left uncovered or when it is spread on fields as a fertiliser.

Some of the gas ends up as a nitrogen deposit in rural areas, affecting biodiversity. An article by the Bureau for Investigative Journalism references studies across the UK and Europe that highlight how agricultural ammonia is affecting biodiversity: “grasslands are losing species, which can hit pollinating insects, and fungi that help trees and other plants to grow are being killed off”.

NH3 also mixes with industrial and car fumes to create a form of ‘particulate matter’ that has been linked to higher death rates, respiratory problems and cardiovascular diseases. In fact, a further investigation by the Guardian, the Bureau of Investigative Journalism and Channel 4 News in 2019 suggested that at least 3,000 human deaths each year could be avoided if agricultural ammonia emissions were halved.

What is the environmental impact of farmed fish?

Fish is often considered to be a lower impact substitute than meat or dairy. While this is generally true, it can very much depend on how the fish is caught or farmed. For example, a 2021 study found that boats trawling – dragging heavy nets across the ocean floor – release as much carbon dioxide as the entire aviation industry. The seabed is a massive carbon sink. By damaging it, we release greenhouse gases and harm biodiversity.

For farmed fish, the key issue is feed. Most farmed fish are fed on fish meal or fish oil, produced from smaller fish like anchovies or herring, or sometimes crops like soy. A fifth of the world’s fish catch is used for fish meal and fish oil production, 70% of which goes to fish farms. Fish farming is therefore responsible for a significant proportion of the emissions, overfishing and other environmental impacts associated with wild-caught fish.

As with other animal feed, this process is incredibly inefficient: feeding and rearing fish on fish meal essentially wastes calories that could otherwise have been directly consumed by humans.

A 2019 study found that farmed fish had higher emissions per 100g of protein than poultry or eggs, although it had substantially lower land-use impacts. Farmed salmon is often cited as the prime example of a high impact fish, due to its carnivorous diet. It can take up to 350 wild caught fish to raise a single farmed salmon.

Factory farming and antibiotic resistance

In 2020, the World Health Organisation (WHO) warned that antibiotics were already failing and that

“without urgent action we are heading for a post-antibiotic era in which common infections and minor injuries can once again kill”.

It says that this is “one of the biggest threats to global health, food security, and development today.”

Over time and due to their overuse and misuse, antibiotics become less effective as bacteria adapt to them and build up resistance. Across the world, it’s estimated that 73% of antibiotics are used on farm animals. A piglet will often receive its first antibiotics within hours of being born. Throughout their life, many animals will be fed antibiotics in their food and water, not to treat illness but to prevent disease or promote growth.

This overuse of antibiotics is intertwined with factory farming. Preventative use of antibiotics allow farms to continue keeping animals including fish in cramped, unhealthy and confined conditions, which would otherwise cause the spread of disease. Antibiotics are also used to make animals grow faster on less food, a key aim of factory farming.

According to Compassion in World Farming, “In the UK, British livestock farmers have made good progress in reducing their antibiotic use, and farm antibiotic use now accounts for about 30% of all British antibiotic use. British pig and poultry farmers have reduced or, in some cases, ended routine use. This progress is welcome, however, much more needs to be done, as antibiotic use remains too high.”

Some alternative animal farming systems, such as organic, ban the routine use of antibiotics. Read more about these certifications here in our article on animal welfare including certification schemes.

Factory farming and zoonotic diseases

An estimated 60% of known infectious diseases and up to 75% of new or emerging infectious diseases are transmitted from animals to humans. These include Ebola and Covid19.

Some of these are transmitted from wild animals, but World Animal Protection says that factory farming also has a significant role to play:

“Driven by global demand for cheap animal foods, the industrialisation of animal production has resulted in a focus on fewer and more genetically similar productive livestock breeds. The transition from subsistence and extensive to more commercial and intensive factory farming systems has resulted in the greatest zoonotic spill overs, because of higher livestock stocking densities, poor hygiene, lower animal welfare standards, and genetically similar breeds with less resilience to disease. Factory farming of pigs, for example, promoted transmission of swine flu due to a lack of physical distancing between animals. Moreover, as livestock population densities increase, more natural habitats are converted into farmland (for grazing or animal feed), which in turn reduces biodiversity and, thus, the ability of ecosystems to provide crucial functions, such as disease regulation or dilution.”

Deforestation fires burning in Amazon
Image from Greenpeace - Christian Braga

Factory farming and Indigenous rights

Animal farming drives an unsustainable demand for land – which in some parts of the world is being stolen from Indigenous communities who have lived there for centuries. In the Amazon, land is taken for cattle ranching or for growing soya, used for factory farmed animal feed.

In March 2022, an investigation by British NGO Earthsight and the Brazilian observatory De Olho Nos Ruralistas found that “Chicken supplied to UK supermarkets is fed with soy connected to violations of Guarani Kaiowa indigenous people's rights”. The report stated that the Guarani Kaiowa people had been evicted off their ancestral lands in Brazil, and that attempts to regain access had been “brutally suppressed” by authorities and landowners.

Tonico Benites, a Guarani Kaiowá leader, told the organisations,

“It's as if soy came from nowhere. There's nothing to identify it so the consumer is not able to see that it comes from an indigenous land."

Factory farming and food insecurity

Almost one in ten people around the world do not have enough to eat. There are many complex reasons for global food security, including the way that food is currently traded and consumed. The overconsumption of meat and dairy in rich countries is part of this complex web.

As discussed above, eating meat, fish and dairy is extremely inefficient. It uses up land, water and other resources that could otherwise be used to directly feed the world’s population.

In 2021, New Internationalist reported that sardinella, a type of small fish, were “being routed away from communities in West Africa to feed salmon, pigs and pets”. It found that in countries like Senegal, this “nutritious superfood” was being processed for farmed fish and animal feed depriving local communities of a vital food source.

In 2022, researchers argued: “The war in Ukraine and the resulting shortages in international markets for cereal grains also underline that less grain should be fed to animals in order to support food security.” Factory farming predominantly relies on such animal feed.

Meat and dairy consumption also contributes to food insecurity through its high emissions. By driving climatic change, it is threatening production of food for many communities now and into the future.

While all forms of meat and dairy farming have high climate impacts, factory farming is a key cause of rising meat consumption. Over the last decade, the UN, scientists and MPs in the UK have all called for us to eat less meat as part of measures to address food insecurity.

What are companies doing about factory farming?

Lots of companies have animal welfare policies, with criteria like ‘freedom from hunger and thirst’. However, for many multinationals, the bar is very low and still allows factory farming. It can therefore be difficult to separate those talking the talk from those actually making changes.

Companies that are serious about changing practices will likely have a certification such as Organic or Pasture For Life, to show they are not using factory farming practices.

Find more information about different animal welfare labels and what they mean in our article.

What can consumers do about factory farming?

plate with 5 stuffed mushrooms

1. Cut down on meat and dairy

Our current rate of meat and dairy consumption is unsustainable and relies on factory farming. If you want to address this damaging system, the best step you can take is to cut down on meat and dairy or cut it out altogether.

Check out our guides to vegan cheese, vegan and plant milks, and meat-free sausages and burgers, and look out for vegan options in many of our guides including chocolate and butter & spreads.

In our shopping  guides we highlight totally vegan companies, as well as vegan products or brands – so you can make sure none of your money is going to companies using animals.

The food feature from our Climate Gap report has further information about meat and dairy consumption, along with food waste.

2. Buy from a farm you know and talk to them about conditions

Farms often sell directly at markets or through delivery. Find a farm you think looks good and spend time reading their website and, if you can, speaking to them. Work out your primary concerns and ask them questions. These are good ones to start with:

  • How do you ensure high animal welfare? Ask about enrichment, transportation and access to pasture.
  • How many days a year can your animals graze outside? The best farms for welfare will ensure their animals have access to outside pasture for the majority (180 days and nights or more) of the year.
  • What is your policy on antibiotic use? The best farms will only use antibiotics to treat animals, rather than to prevent disease or promote growth.
  • How are you reducing emissions and pollution from your farm? They may talk about feed, treatment of slurry or manure, and sustainable use of manure for spraying crops.

3. Look for better meat standards

While they may not be able to address the carbon footprint related to meat and dairy, the strongest animal welfare standards address issues like animal welfare, antibiotics and feed.

Find out more about different certification schemes in our article on animal welfare.

How to avoid companies involved in factory farming

Our ratings track companies' record on factory farming. Companies selling meat, dairy or eggs not labelled as free-range, organic or an equivalent animal welfare standard lose a full mark under Factory Farming. All of the major supermarkets in our supermarket guide lost a full mark under both Animal Rights and Factory Farming.

We also mark companies down if they have links to specific abuses related to factory farming. For example, Morrisons lost a mark under Animal Rights, after an investigation found serious abuses on a UK chicken farm supplying the supermarket. Tesco, Asda, Morrisons and M&S all lose a mark under Habitats & Resources, after a 2019 investigation by the Guardian found that they were likely to have deforestation soya in their meat and dairy supply chains.

Our dairy milk, butter and eggs shopping guides highlight options that are free from factory farming. For example, we recommend organic milk brands like Acorn Dairy, and organic egg brands like Clarence Court Organic (along with recommending non-dairy / non-animal versions).

More and more companies are also moving away from animal products altogether. In our chocolate guide we found eight companies selling only vegan chocolate, including Picari, Beyond Good, Mia and Fairafric. In all our guides, we highlight the vegan alternatives so that you can avoid animal products if you want to.

Shopping guide to milk

In our shopping guide we review 31 brands of dairy milk. We look at industrial farming, animal welfare, pollution, packaging and give our Best Buy recommendations.

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Shopping guide to eggs

Our shopping guide to eggs reviews 43 brands of eggs and vegan egg alternatives.

We investigate egg labelling, vegan egg substitutes, the carbon impact of egg production, and the differences between cage, barn, free range, biodynamic and organic eggs.

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We review 17 vegan cheese brands, look at non-vegan companies making vegan cheese, ethical and environmental issues of the key ingredients of vegan cheese, and give our Best Buy recommendations.

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We look into their sustainability; what they're made from including almond, coconut, hemp, rice and soya; packaging, and who produces them. We shine a spotlight on Alpro, owned by Danone, and make Best Buy recommendations.

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