Three-quarters of a century after the creature became the butt of jokes, scientists are discovering that our species shares a surprising number of traits with the humble chicken. The Italian neuroscientist Giorgio Vallortigara recently demonstrated, for example, that just-born chicks are natural mathematicians. They can track little plastic balls appearing and disappearing behind screens, even when he tried to fool them by moving some balls to another screen. Humans generally fail at the task until they are four years old.
And chicks can do more than add and subtract. They can understand geometry, recognize faces, retain memories, and make logical deductions that Vallortigara insists exceed the capabilities of some of his graduate students. Other neuroscientists are finding that chickens practice self-control, alter their message to fit the receiver, and, in some instances, can feel empathy. Some of these cognitive abilities equal or surpass those of assorted primates, and it is possible that the chicken possesses a primitive self-consciousness.
Vallortigara’s lab is in the cellar of a sixteenth-century convent in Rovereto, an Italian town in the foothills of the Alps. A dapper man in a light-blue shirt and silk tie, Vallortigara was born here in the decade after World War II, when Italy was poor and flocks were critical to survival. “Not to have chickens was not to have eggs,” he says, and that often meant going hungry. As a child, he grew curious about how animals perceived the world.
The idea that animals have mental abilities similar to those of humans has been controversial since the seventeenth-century French philosopher René Descartes declared that they lack minds, reason, and a soul. Animals communicate anger, fear, or hunger with sounds, he noted, but they don’t speak and therefore lack the inner voice that is the very basis of human thought. His famous “I think therefore I am” might be better stated as “I speak therefore I am.” Animals might feel pain or pleasure—“I deny sensation to no animal,” he wrote—but they lack that human quality of greater awareness or cognition. Philosophers, scientists, religious figures, and animal activists have been arguing this point ever since.
Neuroscientists like Vallortigara gather hard data on animal perception. They have learned that chickens see the world in far greater depth and detail than we do. Mammals began as nocturnal creatures to avoid predators like day-loving dinosaurs, while birds preferred the light and therefore have far superior color vision. A red jungle fowl boasts rich reds and blues and greens in its feathers, but the bird perceives a dazzling combination of colors extending into the ultraviolet and beyond human vision. Chickens also use each eye for separate purposes, allowing them to focus on one object—such as potential food—while keeping another eye peeled for predators. This accounts for the odd and jerky head movements of a hen or rooster.
The chicken’s excellent visual system was once thought to be offset by its inability to smell. Recently, a research team studied a domestic flock that did not react when presented with elephant and antelope dung, but grew alert and stopped eating when placed near the droppings of wild dogs and tigers. Like humans, chickens may rely more on their eyes than their noses, but they can catch a whiff of danger. The bird also recalls faces of humans and chickens, and can respond to that individual based on a previous experience. Seeing a favorite hen, for example, will cause a rooster’s sperm production to suddenly increase.
Scientists once scoffed at the idea that fowl have a sophisticated method of communication. “Even if chickens had a grammar,” the cognitive psychologist David Premack wrote in the 1970s, “they would have nothing interesting to say.” Since then, a German linguist has concluded that all fowl have about thirty distinct sounds matched to specific behaviors. For example, the bird uses separate calls to signal whether a predator is approaching by land or by air.
Vallortigara studies chickens primarily because they are inexpensive, hardy, and easy to maintain. Most birds, like mammals, require extensive care of their young, while chickens emerge from their eggs largely capable of fending for themselves and ready to take part in experiments before the external environment influences their behavior. In the old convent cellar, a team of seven PhDs and assorted graduate students in orange shoes and white coats bustle through the narrow and brightly lit hallways, which nevertheless have the air of a dungeon. Vallortigara takes me first to a dark, warm room filled with fertilized eggs that will soon serve as test subjects.
The experiments focus on filial imprinting, in which newly hatched birds attach themselves to the first moving object they see. The researchers show a chick a particular object such as a red cylinder, place the animal in a transparent pen, and hide the cylinder behind one of two opaque screens. The transparent pen then is covered with a screen, and after a delay of up to one minute, they let the chick go to the screen of its choice. The bird finds the imprinted object on the first try, demonstrating a well-developed memory. In another experiment, the cylinder is hidden behind a screen that covers the entire object, while the neighboring screen has a different height or width that would reveal a portion of the object. The bird invariably picks the one disguising the cylinder, a sign of what Vallortigara calls “an intuitive physics.”
Chicks also are capable of adding and subtracting. A young bird presented with an identical cylinder that disappears behind one screen and several that disappear behind the other screen will go to the screen with the larger number of cylinders. If the researchers move a cylinder from one screen to the other, so that the second screen holds more objects, the chick will go to the screen with the most objects. In another experiment, six identical containers are set up in an arc, all of which are the same distance away from the bird but only one of which has feed, and the chick is allowed to find which one has the food. Switch the food container to another position, and the chick will still choose the correct one.
Vallortigara and colleagues also recently determined that chickens have brains with distinct right and left lobes, an attribute long thought to be solely human. Our left hemisphere controls language, the tool that Descartes believed set us apart from other beings, while our right hemisphere orients us to the people and objects around us. A developing chick’s left eye is covered while the right eye faces the shell of the egg. Exposing the right eye of the embryo to light in its last three days in the egg weakens the bird’s visual processing. Once hatched and faced with pebbles mixed with grain, the left side of the normal chicken brain judges what is pebble and what is grain and then pecks only the food, while the altered chick cannot distinguish between the two sets of objects.
Chickens make use of the different halves of their brains for specialized tasks, and, Vallortigara suggests, they can distinguish between animate and inanimate objects. In another experiment, chicks are shown random points of light as well as points of light that mimic a walking hen, cat, or other animal. Chicks invariably prefer the lights that imitate the motion of a biological creature, though not necessarily the hen-like image itself. Normal two-day-old human babies also make this distinction, but many autistic children and adolescents cannot. Vallortigara’s team is exploring whether the disorder is linked to this instinctual ability to interpret biological motion. By pinpointing the genes operating in chicks during biological motion cognition, Vallortigara hopes to understand the mechanisms that might go awry in autistics, a first step in treating the disorder.
In 2012, an Australian philosopher reviewed the scientific literature and concluded “it appears likely that one familiar species, the chicken . . . exhibits primitive self-consciousness.” As a result, he added, “chickens warrant a degree of moral standing that falls short of that enjoyed by persons, but which exceeds the minimal standing of merely conscious entities.” They not only can feel sensation, as Descartes knew, but they may know that they exist and, therefore, that they suffer.
While Vallortigara studies what makes chicks tick, other scientists are probing how chickens feel about living conditions in today’s industrial poultry business. Animal-rights activists
and companies that sell eggs are locked in a battle over how hens are treated, and the research results could determine the fate of billions of birds for decades to come.
The father of today’s egg-laying hen was animal lover, sometime vegetarian, and pacifist Henry Wallace, an Iowan who served in President Franklin Roosevelt’s cabinet and as his vice president during World War II. A farmer deeply concerned with rampant rural hunger during the Depression, Wallace was convinced that making a more productive chicken could help banish poverty. He founded the Hi-Bred Corn Company in 1926, and his son began to breed commercial hybrid layers in 1936. By the middle of World War II, the business was selling laying Leghorns. Its successor, Hy-Line International, is now the world’s largest single producer of egg-laying hens. White Leghorns, which produce white eggs, and Rhode Island Reds, which make brown eggs, are the world’s two primary laying varieties. American hatcheries churn out 500 million egg-laying hens a year, and Wallace’s home state of Iowa produces nearly twice as many eggs as any other U.S. state. The hens lay more than 75 billion eggs a year.
Nine out of ten laying hens in the United States live in wire enclosures called battery cages. Eight birds may be assigned to each cage, without the space to open their wings. Their heads can poke out far enough to peck at the feed bin that runs alongside cages stacked in several tiers, and their waste falls through the wires onto a conveyer belt below. There is no place to roost, dust bathe, or lay eggs in private, three behaviors common to all hens. Vicious pecking, avian hysteria, mysterious deaths, and even cannibalism are often the result. Birds are debeaked, without anesthesia, to limit injuries as they churn out eggs. Disturbing conditions like fatty liver and swollen head syndrome, mouth ulcers, and feet deformities are common. The noise is deafening, the air filled with ammonia, and the animals have a crazed look.
“In no way can these living conditions meet the demands of a complex nervous system designed to form a multitude of memories and make complex decisions,” concludes one poultry researcher. “A gallinaceous madhouse,” is how a shaken Texas naturalist summed up a typical laying shed. Wallace’s vision of affordable eggs for U.S. consumers came true, but there is growing consumer unease with the methods used to produce the billions of eggs laid in the United States annually.
Chickens are excluded from U.S. laws regulating humane treatment of animals raised as food, and there are no international regulations. Banned in the European Union, battery cages are being phased out in a growing number of U.S. states. Costco and Walmart sell only cage-free eggs under their private brands, while Burger King and Subway, among other food purveyors, are committing to non-battery eggs as well. Yet scientists know little about the impact of various sorts of confinement on chickens. A label designating eggs produced in a cage-free environment might trigger images of happy hens tripping across a sunny meadow, but the vast majority of these birds are raised like broilers on the floor of vast, enclosed sheds or in multistory aviaries and are subject to violence, disease, and neuroses. We might feel better, but do the chickens?
A new $1.8 million research facility at Michigan State University in East Lansing is designed to answer that question. Animal welfare scientist Janice Siegford, who is conducting experiments in the boxy building on the outskirts of campus, is part of a new generation of researchers who want to use science to improve the treatment of chickens while accepting the reality of consumer and industry economics. Siegford worries that the debate about battery cages is driven by emotion or economics rather than data, so she has begun tracking the behavior of laying hens living in three different housing systems.
Siegford, athletic and wearing close-cropped hair, is preparing to take freshman and sophomore students on a tour of the facility when we meet. The neuroscientist began her career experimenting on the spinal cords of Mongolian gerbils to understand how neurons are generated, work that could provide clues to treating human paralysis. Frustrated with the field’s tendency to reduce everything to its component parts rather than consider the whole organism, she switched to animal welfare research. “Helping people with paralysis is pretty cool stuff,” she says. “But I thought if I was going to use animals in my research, then I would like it to benefit them directly.”
When the students arrive, Siegford explains the goals of her research program and challenges them to consider difficult questions. “Our idea is to find out what is good for the chickens so that they have a better quality of life. As you go through, consider the pros and cons of chicken health, your health, and economics, too—there’s a lot to think about.” In an anteroom we don white suits designed to protect the seventy-two hundred birds from illness and then enter the wide main hall that leads to a dozen separate rooms. Four contain aviaries, tiers of cages with an open area of litter on one side. Eight have cages that contain perches, dust bathing mats, and screened-off nest boxes—“enriched” cages in poultry parlance. These two systems are the leading alternatives to broiler-shed or battery-cage models.
Siegford guides me into the cloying warmth of an aviary bathed in eerie pink light, with three tiers of cages and an open area on one side of the floor housing several hundred White Leghorn hens. Allowing the birds to roam the floor and tread in dung gives them more freedom and increases the odds that harmful microbes could be transmitted to their eggs. The open area is divided into Astroturf, sawdust, straw, and bare concrete so that researchers can determine which environment appeals the most to the hens and test the microbial load of each flooring material. A student group troops into the room. “Why do some have big bald spots?” asks one. “Chickens are not kind and gentle,” replies Siegford. “They peck at each other and pull feathers out. When a hen lays an egg, her cloaca pushes out and is bright red. In a sea of white chickens, that is startling and attractive and they may peck at that. And some of the spots come from their rubbing against the cage.”
The enriched cage next door gives birds more room for movement than a battery cage, but there is no open floor space where they can gather. Bright-orange curtains close off nest boxes and hens sit on small perches, features absent in battery cages. Another enriched cage includes a greater assortment of perches and nest boxes, as well as small plastic mats designed for dust bathing. Siegford wants to understand what size a nest box must be to assure privacy and what height is optimal for a perch. Getting such small details right is necessary to ensure the birds’ comfort and mental health.
Hens are more likely to die in an aviary, fall prey to cannibalism, or suffer from the higher levels of ammonia and dust stirred up by their movement, says Siegford. Gathering eggs is also more difficult for workers, who must use rakes and slide around on their bellies. The birds in the enriched cages, by contrast, appear to have more bald spots around their necks. “This one’s seriously feather pecked,” she notes as she peers into the cage. “Oooh, that’s bad.”
The research program is in its early stages, so she can’t yet draw firm conclusions, but she’s skeptical that the open-floor approach improves overall chicken welfare. “Aviaries let chickens have more freedom,” she says, “but I don’t think they always use that freedom wisely.” Siegford worries that animal-rights organizations, states, and industry will shift to aviaries before it is clear that they are an improvement. She believes that enriched cages may be the better choice for practical as well as welfare reasons, since the industry already is used to managing caged birds.
How much space a bird needs to live comfortably remains a matter of dispute between activists and industry, and Siegford hopes her research will provide clear answers. Every single hen in the facility is weighed, tagged, and given a welfare quality score, data that might reveal when overcrowding triggers increased violence and disease. The point at which chicken’s social structure, called the pecking order, breaks down is not yet known, although Siegford estimates that the limit is a community of fifty birds.
Stepping back into the hall, she points out a panel regulating water, feed, an
d air temperature for each room. Her goal is to add a sensor that can alert operators if birds go silent or panic en masse, a feature that could become part of commercial laying operations. Observing a flock’s behavior is simpler than attempting to track an individual among thousands, so Siegford and an MSU engineer turned to sensing technology used in the military to track the location and status of soldiers in the field using electronic harnesses. These are too large and expensive to use on chickens, so the pair designed a miniature sensor and went to a pet store and bought a hundred Chihuahua harnesses—“the clerk thought we were crazy”—that could be slipped over a bird. Such a device ultimately could be used to spot depressed appetite or increased pecking among individuals, signaling health or behavioral trouble before they reach epidemic proportions.
More humane environments and better monitoring would benefit layers, but they will not address some of the most disturbing practices in today’s industrial agriculture. Layer hatcheries discard all roosters, and there are no U.S. government regulations on how this should be done. No law prevents abuse of the unwanted animals. Laying operations frequently limit food or starve aging hens to speed molting so that they will resume laying more rapidly.
Within a year or two, a typical laying hen is spent. “We selected chickens to lay eggs at the expense of their own bodies,” says Siegford. “You won’t see a physically healthy hen at the end of her laying cycle no matter what nirvana you put her in. Her body is driving her to lay eggs.” No matter how many perches, dust-bathing mats, or open space are provided to hens, the genetics of the bird works against its welfare. And once their laying days are over, there are no laws governing their destruction, and the hens have almost no economic value except as fertilizer or pet food.
As we step outside and the students depart, Siegford’s faith that science will build a bridge to better chicken welfare wavers. The scale of commercial layer operations boggles her mind. “When you look down the row at a laying house, you can’t see to the end. How many birds are there, and how do you keep track of their welfare? What bothers me is that we are so disconnected from these living beings, and our role as caretakers, in the name of efficiency and cheap food.” And chickens, she adds, evoke less interest and empathy than cows or pigs. “They are like background noise. But not if you really look at them. They use the sun to tell time, their social communication is quite complex, and they are one of the few animals besides primates to alter their message to suit their audience.”
Why Did the Chicken Cross the World? Page 28
