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Battery cages
All animals have behavioral needs--internally motivated behaviors that persist in any environment. Some behaviors are so important that scientific research has found that animals suffer either psychologically or physically if they are unable to engage in them. Animals are still strongly driven to perform certain essential, normal behaviors even after basic physical needs are met, like the provision of water, food, and shelter.
The overwhelming majority of the 280 million egg-laying hens in the U.S. are confined in barren, wire battery cages so restrictive that they cannot even extend their wings. Most cages hold five to ten birds. A typical U.S. egg farm contains thousands of these cages at an average space of just 67 square inches per bird, which affords each hen an amount of floor space smaller than a standard sheet of paper. In battery cages, the following natural behaviors are thwarted.
Photo by benketaro
Nesting
Engaging in nesting behavior--the requirement to seek out a secluded site in which to carefully scrape out and build a shallow nest on the ground--is the most well-documented behavioral need of the egg-laying hen. Studies have documented that hens are highly motivated to gain access to a private nest site when they are about to lay an egg. Hens will even go without food or water if it means they can have a private place to lay their eggs.
Experts on bird behavior suggest that the deprivation of the ability to nest causes birds "significant suffering." Some birds "vacuum nest" in battery cages—that is they go through the motions of building a nest in the absence of nesting materials. Dr. Ian Duncan with the Department of Animal and Poultry Science at the University of Guelph stated, "the biggest source of frustration is undoubtedly the lack of nesting opportunity."
Photo taken at Farm Sanctuary by Garry Choo.
Dustbathing
In a natural setting, hens will regularly bathe in dust to keep their feathers and skin healthy. When dry, loose substrate, such as dirt, wood shavings, or peat, are available, hens will typically dustbathe every other day. During a dust-bath, hens lie in and rub dust through their feathers before standing up and shaking off the loose dust particles. Hens dustbathe in order to rid their feathers of parasites, to cool off, and some scientists suggest they even do it just for pleasure.
Caged hens still have the natural urge to dustbathe, even when litter or other dustbathing materials are not present. In fact, battery-caged hens will try to dustbathe on the wire floor of the cage, sometimes leading to feather loss. In battery cages, hens are denied this important natural behavior.
Photo by mamamusings.
Perching
Battery cages prohibit hens from perching and roosting, natural behaviors hens perform under normal circumstances. Scientific research indicates that the foot of a chicken is “anatomically adapted to close around a perch,” meaning their feet evolved to hold onto branches. Chickens initially perched and roosted high up in trees in order to keep safe from predators and other aggressive birds, but now it’s a behavior they’ve evolved to do. In addition to being an intrinsic natural behavior, perch use is important for maintaining bone strength.
Photo by Ervín Pospíšil
Exploring
Hens are naturally intelligent and inquisitive animals. Scientists contend that exploratory behavior is important to chickens for several reasons: it satisfies the drive to acquire information about their environment, it creates competency, and is also an end in itself. Exploratory behavior may continue even in the absence of goal-directed behavior like foraging for food or seeking a suitable nest site, as chickens continue to explore even when the these needs have been met. Studies have proven that chickens are so driven to explore that they will forage for feed on the ground rather than eat the same food freely available in a feeder.
Photo by Lilly M
Exercising
Hens kept in battery cages are confined so tightly that they are unable to exercise. Ample scientific evidence documents that keeping birds in cages restricts their natural movement so much that it results in bone weakness. In a natural setting, movement causes strains and stresses to muscles and bones that keep the skeletal system strong. Battery cages prevent birds from exercising, which leads to weak bones.
As Dr. Bernard Rollin with the Department of Animal Science at Colorado State University stated, "The most obvious problem is lack of exercise and natural movement. Under free- range conditions, hens walk a great deal. Wing flapping, which is common in free-range animals, is also prevented in cages. Comfort behavior is likewise truncated, as is leg stretching and preening. Research has confirmed what common sense already knew—animals built to move must move."
