Egg Farming
Eggs are often considered a top source of protein, but are they really necessary as part of a healthy, balanced diet? And what do terms like “cage free” and “barn laid” actually mean? We delve into the implications of our current consumption of eggs, for the chickens, the environment, our health, and the health of others.
About Layer Hens
With most farm animals out of sight and out of mind, society has come to perceive most animals as one-dimensional, interchangeable units within a species. The animals that are bred to be used for food, clothing, and entertainment, have much more to them than the food or production value we have assigned them. Here are some interesting facts about chickens that you might not already know -
Every hen is unique
Like humans, every chicken is unique. Research has shown that chickens have different personalities, which impacts the way they respond to stimuli, situations, and interact with others. Understanding that animals have personalities helps us see them as the individuals that they are [1]. Rescuers who care for ex-layer hens often point out how each hen is different. Some absolutely love attention, cuddles, and pats, while others are more independent and happy to be left alone.
Rescue hens experiencing freedom for the first time.
A hen doesn’t naturally produce 300 eggs
The ancestor of the modern-day layer hen, the Red Jungle Fowl, only lays 10-20 eggs a year [2]! This is a stark contrast to layer hens, who now produce around 300 eggs in the same time frame [3]. Selective breeding, artificial lighting, and feed control have created this unnatural production, which significantly impact the hens. An eggshell is made almost entirely of calcium, and an overproduction results in a calcium deficiency for hens. This deficiency can cause osteoporosis, making them prone to bone fractures [3]. A study in Denmark observed fractures in 53% to 100% of flocks in cage-free systems and in 50–98% of birds in enriched cages [4].
Chickens eat their eggs
Chickens will sometimes choose to eat their own unfertilised eggs, as they contain vital nutrients for their health, like calcium, and because they like the taste. If left alone with their eggs, they will break them open and eat the insides and shells [5]. Rescuers have said that the hens get very excited when they can eat their eggs. The egg industry obviously denies them from eating the eggs, as it reduces the amount they can sell to the public.
To learn more surprising facts about chickens, their sentience, intelligence, and social behaviours, please read the Chicken Farming issues page.
The Industry
There are more than 7 billion layer hens around the world [6]. If each hen produces 300 eggs, it means there are around 2,100,000,000,000 (2 trillion and 100 billion) eggs produced a year. People consume eggs either on their own, or in products like muffins and cakes, and millions are also used by the medical industry, in vaccinations. On average, a person consumes around 200 eggs per year [7]. In order to meet consumer demand with minimal costs, chickens around the world are raised in appalling conditions and undergo routine mistreatment.
Australian Standards
In June 2021, Australia had 21,947,297 layer hens, who produced over 6.22 billion eggs for human consumption. Beyond layer hens, there are also an additional 7,179,932 pullets, who are female chicks waiting to enter the system once they are able to produce eggs [8].
Housing
Farming eggs is pretty standardised around the world, using three types of egg production systems; caged, cage-free, and free-range [9]. Farms typically hold 20,000-100,000 hens, however, smaller “family” farms may have up to 1,000. All systems cause hens stress, due to boredom and frustration from confinement and the inability to establish a social hierarchy. This stress can create problematic behaviours such as cannibalism, bullying, and feather pecking. Providing enrichment, like on free-range farms, does not always solve this problem. Hens are then competing for the limited perches and nesting boxes, which can make them more aggressive towards one another [10].
Caged
Globally, 86% of layer hens are kept in cages, meaning they are unable to exhibit any natural behaviours [9]. Each shed contains parallel rows of tiers of cages. A single shed can hold up to 100,000 individuals [11]. The standard battery cage holds between 4-6 hens, while newer “enriched” cages hold 60-100 hens. These are not common in Australia. Although cage sizes can vary, all types give a hen the space of an A4 piece of paper.
Inside an Australian caged shed.
Credit: Animal Liberation.
Caged Eggs Continued
Hens in a cage system can never stretch their wings, dust bathe, explore, or forage. They will also never stand on solid ground, as the cages have sloped wire floors, allowing the eggs to roll out and their waste to be collected on a conveyor belt below them [9]. The wire floor often causes hens to develop toe pad hyperkeratosis, which is where the skin on their feet thickens and they have deep, open sores and swelling.
Wire floors inside a cage.
Credit: Animal Liberation.
Cage-free or Barn Laid
A cage-free farm means that hens live inside a shed with up to 30,000 others. They may be given nesting boxes and perches, which allow them to exhibit some of their natural behaviours. While this housing system does allow the birds to walk around, it still treats them as machines and ignores their natural social structures. Like in the cages, the floor is most often not solid, so that the sheds do not have to be cleaned as their waste falls below them [9].
Inside an Australian cage-free shed.
Credit: Animal Liberation.
Free-range
Free-range systems are the same as cage-free, however, the hens are sometimes allowed to go outside during daylight hours [9]. Unfortunately, the sheds are so crowded that it can often be impossible for all of the hens to make it outside.
Breeder Flocks
Hens and roosters used for producing fertile eggs live in sheds with litter or wire mesh flooring. After 12 months of being confined to the sheds, they are killed due to a decrease in productivity. The sheds are cleaned after the birds are removed, meaning they live in their waste for the entire period [12 PDF].
Mass Culling of Male Chicks
A portion of eggs are hatched in order to replace spent layer hens (more on this below). Of the hatched individuals, the male chicks are killed on their first day of life, as they are deemed ‘useless’ by the egg industry. Males have no purpose, as they cannot lay eggs and do not grow large enough to become meat. They are either thrown alive into a macerator to be ground up, suffocated, or gassed to death [13]. All methods are incredibly cruel, however, some take over a minute to die from asphyxiation during gassing and suffocation. All egg purchases support the killing of male chicks. Approximately 6 billion males are killed every year around the world [14].
Animal Liberation exposed the maceration of chicks on Australian farms in 2016.
Debeaking
Boredom, frustration, competition, and an inability to establish a proper social hierarchy can result in increased aggression and pecking at one another. Instead of reducing flock numbers, increasing enrichment, and banning the cage, the industry attempts to address this behaviour by trimming the beaks of the chickens, known as debeaking [15 PDF]. A chicken’s beak is a complex sensory organ, with numerous nerve endings, and a cluster of highly sensitive mechanoreceptors in the tip. Their beaks allow them to manipulate food and other objects for nesting, exploring, drinking, preening, and defence [16]. In Australia, most layer hens have the tip of their beak seared off by a hot blade. This procedure is incredibly painful, leaving many birds with chronic pain and traumatic-neuromas [17 PDF]. Hens tuck their bill under their wings and lessen the amount of pecking and preening they do, and exhibit behaviour changes for months after the procedure [18].
Forced Moulting
Some farmers may try to prolong their flocks’ ability to produce eggs with ‘forced moulting’. This is achieved by withdrawing feed for two weeks or providing them with low-quality feed to reduce their body weight, because it reinvigorates egg production. Forced moulting is incredibly cruel for the hens [19].
Killed at 18 months old
Naturally, a hen can live for up to 12 years, but on egg farms, they are only kept alive for 18 months. After just 12 months of laying, a layer-hen’s egg production rate slows, making them no longer economically viable. As a result, the industry considers them ‘spent’ and they are sent to slaughter. Removing hens from the cages and sheds is known as ‘depopulation’ [20].
On a cage egg farm, the workers are known as ‘rippers’ because of the way they roughly remove the hens from their cages. On a cage-free or free-range farm, workers are called ‘catchers’. In both situations, workers are allowed to carry up to 5 birds in each hand, often by their fragile legs. The birds are then placed into a trolley or crate, depending on the slaughter method.
Hens being ripped from their cages
Credit: Animal Liberation
Layer hens are either gassed to death or sent to a slaughterhouse where they will have their throats slit, like broiler chickens [23]. Due to their poor health and small weight, their bodies are considered low-quality. As a result, their remains are used for pet food or in lower-quality products for humans, like stocks and soups [24].
Layer hens in gas chamber
Credit: Animal Liberation
In 2019, Animal Liberation exposed the depopulation process and the gassing of spent layer hens on an Australian egg farm.
The Environment
Egg production is having an impact on the environment, in terms of land use, resource use, waste, and pollution. From an environmental perspective, switching to plant-based foods will reduce the amount of land we need to clear for animal agriculture and animal feed, as well as the water, waste, and pollution associated with it.
Land
Although it is great that more consumers are switching their demand for caged eggs to free-range, it would be impossible to raise all 7+ billion hens on free-range farms with enough space to exhibit natural behaviours. The amount of land required for them would cause more land clearing, a decline in wildlife populations, and increased pollution. Currently, with approximately 86% of hens in cages, a kilogram of eggs needs 6.27 square meters of land. If we were to move to entirely non-cage egg systems (cage free or free range) the amount of land needed would increase dramatically. Keep in mind that even in these non-cage systems, chickens are predominately raised in crowded sheds, with limited room to move and little to no enrichment [25].
Looking at land use per 100 grams of protein (2018), eggs ranked 10th.
Resource Use
It will always be more efficient to use the feed and water for human consumption rather than giving it to an animal who will then be slaughtered. It takes approximately 2.3 kilograms of food and 578 litres of freshwater to produce just one kilogram of eggs [23]. If we break this down, for 100 grams of egg protein, 521 litres of freshwater is required! This differs greatly from plant-based foods, like tofu, which requires 149 litres per kilogram, or 93 litres per 100 grams of protein [25].
The amount of food and water that chickens require changes depending on the housing system. Chickens kept in cages are unable to exercise and therefore require less food than those in sheds or on free-range farms. Chickens in sheds need approximately 14% more food, free-range need about 18% more, and organic require roughly 20% more [27]. The increase in food means that the land required per kilogram of eggs will also increase.
Layer hens on Australian caged egg farm.
Credit: Animals Uncovered
Waste and Pollution
Waste from an egg farm includes dead birds, faecal matter, chemicals and medication, unusable eggs, water, feed, feathers, as well as plastic, cardboard, gloves, and other general waste [28 PDF, 29 PDF]. Dead birds are often sent to a rendering plant to become food for farmed animals, like other chickens, pigs, ducks, and fish [30 PDF]. Other organic waste from caged farms is collected and processed off-site and is regularly used in agriculture. While crops do need fertiliser, the amount of organic waste used can pollute the environment. Other farms may burn or bury the litter. Inorganic waste, like plastic and gloves, are sent to landfill.
When organic waste is stored on-site, there is a chance that nutrients will be exported with surface water runoff, meaning it can spread into surrounding water bodies and cause eutrophication. This can promote the growth of algae or create high nitrate levels, which are toxic to wildlife and humans. Nutrients can also leach into the soil, contaminating groundwater. The excess nutrients and salts affect the soil profile and impact plant growth and the environment [31 PDF]. Per kilogram of eggs, approximately 21.76 grams of excess nutrients enter the surrounding environment, while soy, in comparison, releases just 6.16 grams [32].
When analysing the production of greenhouse gases across the supply chain of various foods, plant-based products on average produce 10-50 times less than most animal products. The production of a kilogram of eggs produces 4.5 kilograms of CO2 [33], or 4.21 kilograms of CO2 per 100 grams of protein. In contrast, tofu produces 1.98 kilograms of CO2, and peas just 0.44 kilograms, per 100 grams of protein [34].
Waste on underneath the cages.
Credit: Animal Liberation
Health Impacts
Your Health
There is a lot of contradictory information regarding the effects of eating eggs on our health. Some research suggests that eggs increase our risk of heart disease due to their cholesterol and saturated fat content, while others say it reduces our chances – making it difficult for us to know what information to trust. Essentially, our bodies naturally produce all the cholesterol that we need, meaning there is no need for us to eat additional amounts. When there is too much cholesterol in your blood, it builds up the walls of our arteries and can cause a form of heart disease, known as atherosclerosis. As the arteries become narrow, blood flow to the heart is slowed or blocked [35]. While more research is needed, studies have also suggested a link between the consumption of eggs and hormone-sensitive cancers, like prostate, breast, and ovarian cancer [36, 37, 38].
Additionally, eggs are considered one of the most bacteria-filled foods, as they are laced with salmonella. While cooking can get rid of salmonella, there is a chance that some bacteria can remain, causing bacterial infections or food poisoning [39].
With eggs being one of the highest cholesterol-containing foods, and having a possible chance of increasing cancer risks, thankfully we get all of the same nutrients from plant-based foods that don’t contain cholesterol. Another benefit of opting to eat plants is that they contain high amounts of fibre, which is necessary for promoting healthy digestion! See below for the different sources of plant-based nutrients.
Nutrient Sources
Protein:
Legumes (soybeans, tempeh, lentils, tofu, kidney beans, chickpeeas, lima beans), peas, quinoa, oats, spinach, mycoprotein, seitan, peanut butter, wholewheat, flaxseeds, nuts and seeds (almonds, walnuts, hemp seeds, artichokes, buckwheat, chia, pumpkin seeds, hazelnuts, cashews), dark-coloured greens (kale, broccoli). [40, 41]
Choline*
Broccoli, Brussels sprouts, brown rice, chickpeas, lentils, tofu. [42]
*too much choline can be damaging, and eggs are the richest source of this nutrient.
Lutein
Spinach, kale, mustard greens, collards, green peas, summer squash, brussels sprouts, broccoli, and yellow carrots.
Vitamin D
Sunshine, mushrooms (tip, leave your mushrooms in the sun before cooking them for an extra Vitamin D boost), fortified* soy milk, fortified* orange juice, fortified* almond milk, fortified* tofu.
Did you know that only the eggs from hens who have access to outdoors contain vitamin D?
*because even animal products only naturally contain small traces of vitamin D, it is important to eat vitamin fortified foods, or have regular (and safe) exposure to the sun!
Folate
Legumes (lentils, chickpeas, kidney beans, pinto beans), peas, asparagus, leafy greens (spinach, kale, rocket), beetroots, citrus fruits (oranges, grapefruits, lemons, limes), Brussels sprouts, broccoli, nuts and seeds (flax, walnuts), bananas, papaya, avocado, fortified grains [43].
Vitamin A
Broccoli, carrots, spinach, capsicum, cabbage, sweet potato, kale, squash, collards, celery, lettuce, tomato, mangos, grapefruits, cantaloupe, apricots, watermelon, passionfruit, blueberries, pistachios, black-eyed peas, paprika, tofu [44].
Public Health
As discussed in our blog about broiler chicken farming, people who work or live near chicken farms are at risk of serious health issues. Poultry farmworkers are exposed to bacterial toxins, dust, and adverse odours, leaving them with the potential to suffer from respiratory reactions, airway irritation, inflammation, decreased lung function, stress, and itchy, red, and watery eyes [45, 46, 47]. Workers are also exposed to a high level of noise inside the sheds, which can damage their hearing [48]. People who live near the farms, hatcheries, and slaughterhouses are also at risk due to hazards in the air, water, and soil.
As seen with the Melbourne COVID19 outbreak, workers are also at risk of catching zoonotic infections – such as avian bird flu. Zoonotic disease spreads from animal to animal, and animal to human. Although bird flu has not yet mutated to be infectious from human to human, it is completely possible that it could mutate to do so [49, 50].
What’s Next?
Although it is great to see more people opting for cage-free or free-range eggs, unfortunately no system is perfect, and all egg systems contribute to the deaths of male chicks and spent layer hens. Beyond eggs, buying pre or partial-made products (such as cake mixes, quiches, and pastries) is most likely still supporting caged eggs, as they are cheaper for the companies who produce these products.
The thought of cutting eggs out of your diet might seem a little daunting, but thanks to the amazing range of plant-based alternatives that are available, it doesn’t have to be! By reducing or ending our demand for eggs, we can save billions of chickens from a life of misery and pre-mature death, while protecting the environment, improving our own health, and the health of others as well.