Explainer
Why Dairy Is Hiding in So Many Foods, Explained
Food•11 min read
Explainer
You probably knew chickens in battery cages are crammed in tight — but did you know about the neverending light and reproductive control?
Words by Seth Millstein
If you’ve eaten an egg recently, it probably came from a hen who was raised in horrific conditions in a battery cage. These small, cramped, relentlessly bright cages are physically excruciating for the chickens unfortunate to be housed and forcibly laying eggs in them, and animal welfare groups have long been pushing to ban them. But although they’ve achieved some success on that front, battery cages are still legal in the U.S., and the majority of egg-laying hens in the country are still forced to live in them, enduring particularly cruel forms of reproductive torture throughout their short lives.
A battery cage is a wire enclosure that egg-laying hens — or layer hens, as they’re more commonly called — are confined to on factory farms. They spend the entirety of their lives in them, laying roughly one egg per day, until they’re slaughtered for meat. A single egg-producing factory farm may confine thousands of hens at a time in these cages.
Battery cages are extremely cramped. Typically, each one contains 4-5 chickens, and each chicken has around 67 square inches to herself — less than the surface area of an 8.5 by 11 sheet of paper. Hens in battery cages do not have enough room to fully stretch their wings or extend their necks, let alone walk, fly or do any number of other things that chickens do in their natural habitats.
Though some individual farmers had experimented with housing chickens in cages in the 1930s, battery cages first rose to prominence after World War II. In their original incarnation, they were bigger than they are now and only housed one bird at a time, but they gradually became smaller and more populated.
They’re called “battery cages” because they’re stacked on top of each other in rows, making them look like cells in a battery.
On factory farms, efficiency is the name of the game, and space is at a premium. Battery cages were designed to maximize egg output using as little space as possible; more chickens per square foot means more eggs, and thus more profit, per square foot. In addition, chickens in cages require less oversight than chickens in a pasture, so farmers are free to devote their time to other tasks.
All of this is done without regard for the chickens’ wellbeing, and as such, they’re the ones who bear the physical and psychological toll of these cost-saving measures.
According to the US Department of Agriculture, around 74 percent of all layer hens in the country are languishing in battery cages. That’s 243 million hens at any given point.
Battery cages inflict severe physical and emotional damage on hens in several ways. Most of this is simply due to how cramped they are, but some other aspects of the process are harmful as well.
Molting is a naturally occurring part of every chicken’s life that occurs every winter. As temperatures cool, chickens shed their old feathers and grow new ones. Growing new feathers requires a lot of resources, so chickens naturally stop laying while they’re molting. This pause also gives their reproductive systems time to recover from the constant egg-laying during spring and summer.
This is all natural and healthy. But layer hens are often subject to forced molting, which is a different story entirely. Forced molting is the practice of intentionally starving hens for weeks at a time, causing them to lose feathers, drastic amounts of body weight, and in some cases, their lives. This is done because, when the hens are finally fed again, their bodies resume producing eggs at a high rate for a short period of time.
Most chickens lay eggs during the spring, when there’s more daylight each day. The evolutionary reason for this is to allow chicks to benefit from the warm months of summer when food is plentiful. Conversely, as daylight hours grow shorter, hens produce fewer eggs, since raising chicks in cold weather is more perilous.
In battery cages, hens are exposed to artificial lighting for 18 hours every day. The goal is to “trick” the birds’ bodies into thinking that it’s perpetually spring, which leads them to produce more eggs than their bodies otherwise would. Most hens in battery cages experience little to no natural sunlight during their lives.
A human’s bones become brittle if they don’t maintain a minimum level of physical activity, and the same is true for chickens. Because of how little movement they’re afforded, hens in battery cages frequently develop osteoporosis, a painful condition that weakens their bones and makes them more susceptible to fracture and breakage.
This is so common that there’s an acronym for it: CLO, or cage-layer osteoporosis. One 2004 study found that as many as 89 percent of commercial layer hens have osteoporosis, while a 2008 study found that almost one-third of all hens suffered bone fractures during the the period between their removal from the cage and their eventual slaughter.
A related, even worse condition is Cage Layer Fatigue (CLF). Chickens need calcium to produce eggs, and normally, this calcium comes from their diet. But because layer hens are forced to produce an unnatural number of eggs, their bodies end up drawing calcium from their bones instead. Like osteoporosis, this weakens their bones; unlike osteoporosis, it weakens them so much that the affected birds are paralyzed, and unable to stand or move.
In battery cages, hens spend their entire lives on a wire floor. This is terrible for their feet, and results in painful and sometimes fatal foot problems.
For instance, caged chickens often develop hyperkeratosis, a thickening of the pads on the bottom of their feet that can lead to painful inflammation and open sores. They’re also prone to having overgrown toenails, which is a much more serious condition than it may seem at first glance.
A chicken’s toenails grow continuously until they die. In healthy environments, chickens file their nails down naturally by digging, scratching and simply walking around. But caged chickens aren’t afforded any of these luxuries, and as a result, their nails become overgrown.
Over time, their nails can become so curved that they catch on the wire floor of the cage. In addition to causing painful tears in their flesh, this sometimes traps the birds entirely, preventing them from accessing food and water, and ultimately leading to their death by starvation.
Chickens have complex social lives, and wild flocks maintain cohesion and harmony by establishing an internal hierarchy, also known as a pecking order. But this is impossible in battery cages; due to lack of space, hens can’t avoid one another, and thus can’t develop or maintain dominance hierarchies. This leads to increased aggression and fighting among hens.
That’s bad enough, as chickens can be injured or killed when fighting with one another. But the way factory farms have “solved” this problem is arguably even worse: by cutting off chickens’ beaks at birth.
In order to prevent chickens from pecking one another, farmers slice off their beaks hours after they’re born. This is a painful process that’s performed without anesthetic, and can leave the birds with chronic pain for weeks or months afterwards.
Debeaking, as it’s called in the industry, is only carried out to prevent chickens from fighting with one another — which wouldn’t be a problem in the first place if they were given enough space to move around, socialize and engage in normal chicken behavior.
In a healthy environment, such as a well-maintained backyard, chickens can live for a decade or more. Battery hens, however, are killed after about two years, as that’s when their egg production begins to decrease.
Some farmers keep laying hens in what are generously called “enriched cages.” These are meant to be a healthier, more humane alternative to battery cages. In practice, they’re a marginal improvement at best, and still harm chickens in most of the same ways.
Enriched cages are slightly bigger than battery cages, and they have perches for the birds to sleep on and nests for them to lay eggs in. But they still aren’t big enough for birds to flap their wings, preen, dust bathe or avoid pecking from other birds, and many do not have enough perches for all of the birds to sleep at once. Several studies have shown that enriched cages do not improve the health outcomes of hens who live in them.
As more people learn about the barbaric nature of battery cages, several jurisdictions around the world have taken steps to phase out, limit or outright ban them.
As of this writing, the following countries have banned battery cages entirely:
The European Union has also banned battery cages, and in 2021, announced a plan to phase out the use of all cages in animal agriculture by 2027. However, there have been reports that this plan may be abandoned due to pushback from the meat lobby, and concerns that it would raise prices. Representatives for the EU have denied that they’re dropping the plan, though, and as of this writing, it’s unclear whether the ban will be implemented or not.
There’s no federal law in the U.S. banning the use of battery cages. However, many states have taken it upon themselves to either limit or prohibit their use on egg farms.
The following states have either passed outright bans or, alternatively, gradual phase-outs of battery cages:
With the exceptions of Rhode Island and Utah, all of the above states also have laws prohibiting the in-state sale of eggs that came from hens who were raised in battery cages. Massachusetts passed additional legislation outlining very specific and strict standards for housing layer hens, which includes a specific ban on enriched cages.
Cage-free eggs come from hens that are not confined in any type of cage, battery or otherwise. The nature of cage-free environments, including the amount of space afforded each hen, varies from farm to farm, but in general, hens raised on cage-free farms are able to walk around, dust bathe, spread their wings, lay eggs in nests and engage in other normal chicken behaviors that hens in battery cages can’t. In order to be certified cage-free by the USDA, the chickens also must have unlimited access to food and fresh water.
Cage-free farms are, without question, significantly better for chickens’ well-being than battery cages. One study found that raising a hen in a cage-free environment will spare them thousands of hours of pain that they otherwise would have suffered in a battery cage. But they’re far from perfect. Many cage-free hens still don’t have access to the outdoors and are instead kept in crowded indoor buildings; in addition, many cage-free chickens are still debeaked, and on especially overcrowded farms, cage-free chickens can have a higher mortality rate than their caged counterparts, due to how tightly they’re packed together.
As a consumer, the best way to signal your displeasure with these poor animal welfare conditions is to refrain from buying eggs that were produced in farms that use battery cages.
If you’d like to scrap eggs from your diet entirely, there are plenty of plant-based proteins that are just as nutritious and infinitely more ethical than most eggs you’d find in stores. There are also several plant-based egg substitutes.
If you’re buying eggs in a grocery store, they should ideally be Certified Humane pasture-raised. This means the hens were raised without cages on an actual pasture with grass, a healthy amount of space (108 square feet per bird, per Certified Humane standards), a nest, a roost, protection from predators and, in general, more things chickens need to live healthier lives.
If pasture-raised eggs aren’t an option, free-range is the next-best thing. The name is a bit misleading; “free-range” hens, while not caged, are given around two square feet of outdoor space each, for six hours a day. In practice, free-range farms are often open-air warehouses with concrete or dirt floors. Though not as humane as pasture-raised eggs, free-range eggs are certainly better than battery cages.
Eggs labeled “cage-free” are more ethical than those produced in battery cage farms. As the name implies, the chickens aren’t confined to cages, which reduces their suffering significantly. But cage-free chickens still suffer cramped conditions, and usually spend their entire lives indoors with only artificial light.
Battery cages inflict so much misery on hens that it’s difficult to justify their use on factory farms, or defend grocery stores and restaurants that source their eggs from battery cage farms. Thankfully, significant parts of the world are beginning to recognize this and take action against battery cages. Hopefully, these trends will continue, and battery cages will eventually be a thing of the past.
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