The chickens that saved Western civilization were discovered, according to legend, by the side of a road in Greece in the first decade of the fifth century B.C. The Athenian general Themistocles, on his way to confront the invading Persian forces, stopped to watch two cocks fighting and summoned his troops, saying: “Behold, these do not fight for their household gods, for the monuments of their ancestors, for glory, for liberty or the safety of their children, but only because one will not give way to the other.” The tale does not describe what happened to the loser, nor explain why the soldiers found this display of instinctive aggression inspirational rather than pointless and depressing. But history records that the Greeks, thus heartened, went on to repel the invaders, preserving the civilization that today honors those same creatures by breading, frying and dipping them into one’s choice of sauce. The descendants of those roosters might well think—if they were capable of such profound thought—that their ancient forebears have a lot to answer for.

Chicken is the ubiquitous food of our era, crossing multiple cultural boundaries with ease. With its mild taste and uniform texture, chicken presents an intriguingly blank canvas for the flavor palette of almost any cuisine. A generation of Britons is coming of age in the belief that chicken tikka masala is the national dish, and the same thing is happening in China with Kentucky Fried Chicken. Long after the time when most families had a few hens running around the yard that could be grabbed and turned into dinner, chicken remains a nostalgic, evocative dish for most Americans. When author Jack Canfield was looking for a metaphor for psychological comfort, he didn’t call it “Clam Chowder for the Soul.”

How did the chicken achieve such cultural and culinary dominance? It is all the more surprising in light of the belief by many archaeologists that chickens were first domesticated not for eating but for cockfighting. Until the advent of large-scale industrial production in the 20th century, the economic and nutritional contribution of chickens was modest. In Guns, Germs, and Steel, Jared Diamond listed chickens among the “small domestic mammals and domestic birds and insects” that have been useful to humanity but unlike the horse or the ox did little—outside of legends—to change the course of history. Nonetheless, the chicken has inspired contributions to culture, art, cuisine, science and religion over the millennia. Chickens were, and still are, a sacred animal in some cultures. The prodigious and ever-watchful hen was a worldwide symbol of nurturance and fertility. Eggs hung in Egyptian temples to ensure a bountiful river flood. The lusty rooster (a.k.a. cock) was a universal signifier of virility—but also, in the ancient Persian faith of Zoroastrianism, a benign spirit that crowed at dawn to herald a turning point in the cosmic struggle between darkness and light. For the Romans, the chicken’s killer app was fortunetelling, especially during wartime. Chickens accompanied Roman armies, and their behavior was carefully observed before battle; a good appetite meant victory was likely. According to the writings of Cicero, when one contingent of birds refused to eat before a sea battle in 249 B.C., an angry consul threw them overboard. History records that he was defeated.

But one major religious tradition—ironically, the one that gave rise to matzo-ball soup and the Sunday chicken dinner—failed to imbue chickens with much religious significance. The Old Testament passages concerning ritual sacrifice reveal a distinct preference on the part of Yahweh for red meat over poultry. In Leviticus 5:7, a guilt offering of two turtledoves or pigeons is acceptable if the sinner in question is unable to afford a lamb, but in no instance does the Lord request a chicken. Matthew 23:37 contains a passage in which Jesus likens his care for the people of Jerusalem to a hen caring for her brood. This image, had it caught on, could have completely changed the course of Christian iconography, which has been dominated instead by depictions of the Good Shepherd. The rooster plays a small but crucial role in the Gospels in helping to fulfill the prophecy that Peter would deny Jesus “before the cock crows.” (In the ninth century, Pope Nicholas I decreed that a figure of a rooster should be placed atop every church as a reminder of the incident—which is why many churches still have cockerel-shaped weather vanes.) There is no implication that the rooster did anything but mark the passage of the hours, but even this secondhand association with betrayal probably didn’t advance the cause of the chicken in Western culture. In contemporary American usage, the associations of “chicken” are with cowardice, neurotic anxiety (“The sky is falling!”) and ineffectual panic (“running around like a chicken without a head”).

The fact is that the male of the species can be quite a fierce animal, especially when bred and trained for fighting. Nature armed the rooster with a bony leg spur; humans have supplemented that feature with an arsenal of metal spurs and small knives strapped to the bird’s leg. Cockfighting is illegal in the United States—Louisiana was the last state to ban it, in 2008—and generally viewed by Americans as inhumane. But in the parts of the world where it is still practiced, legally or illegally, it has claims to being the world’s oldest continual sport. Artistic depictions of rooster combatants are scattered throughout the ancient world, such as in a first century A.D. mosaic adorning a house in Pompeii. The ancient Greek city of Pergamum established a cockfighting amphitheater to teach valor to future generations of soldiers.

The domesticated chicken has a genealogy as complicated as the Tudors, stretching back 7,000 to 10,000 years and involving, according to recent research, at least two wild progenitors and possibly more than one event of initial domestication. The earliest fossil bones identified as possibly belonging to chickens appear in sites from northeastern China dating to around 5400 B.C., but the birds’ wild ancestors never lived in those cold, dry plains. So if they really are chicken bones, they must have come from somewhere else, most likely Southeast Asia. The chicken’s wild progenitor is the red junglefowl, Gallus gallus, according to a theory advanced by Charles Darwin and recently confirmed by DNA analysis. The bird’s resemblance to modern chickens is manifest in the male’s red wattles and comb, the spur he uses to fight and his cock-a-doodle-doo mating call. The dun-colored females brood eggs and cluck just like barnyard chickens. In its habitat, which stretches from northeastern India to the Philippines, G. gallus browses on the forest floor for insects, seeds and fruit, and flies up to nest in the trees at night. That’s about as much flying as it can manage, a trait that had obvious appeal to humans seeking to capture and raise it. This would later help endear the chicken to Africans, whose native guinea fowls had an annoying habit of flying off into the forest when the spirit moved them.

But G. gallus is not the sole progenitor of the modern chicken. Scientists have identified three closely related species that might have bred with the red junglefowl. Precisely how much genetic material these other birds contributed to the DNA of domesticated chickens remains a matter of conjecture. Recent research suggests that modern chickens inherited at least one trait, their yellow skin, from the gray junglefowl of southern India. Did a domesticated breed of G. gallus spread initially from Southeast Asia, traveling either north to China or southwest to India? Or were there two separate heartlands of domestication: ancient India and Southeast Asia? Either scenario is possible, but probing more deeply into chicken origins is hindered by an inconclusive DNA trail. “Because domesticated and wild birds mixed over time, it’s really difficult to pinpoint,” says Michael Zody, a computational biologist who studies genetics at the Broad Institute of Harvard and MIT.

The chicken’s real star turn came in 2004, when an international team of geneticists produced a complete map of the chicken genome. The chicken was the first domesticated animal, the first bird—and consequently, the first descendant of the dinosaurs—thus honored. The genome map provided an excellent opportunity to study how millennia of domestication can alter a species. In a project led by Sweden’s Uppsala University, Zody and his colleagues have been researching the differences between the red junglefowl and its barnyard descendants, including “layers” (breeds raised to produce prodigious amounts of eggs) and “broilers” (breeds that are plump and meaty). The researchers found important mutations in a gene designated TBC1D1, which regulates glucose metabolism. In the human genome, mutations in this gene have been associated with obesity, but it’s a positive trait in a creature destined for the dinner table. Another mutation that resulted from selective breeding is in the TSHR (thyroid-stimulating hormone receptor) gene. In wild animals this gene coordinates reproduction with day length, confining breeding to specific seasons. The mutation disabling this gene enables chickens to breed—and lay eggs—all year long.

Once chickens were domesticated, cultural contacts, trade, migration and territorial conquest resulted in their introduction, and reintroduction, to different regions around the world over several thousand years. Although inconclusive, evidence suggests that ground zero for the bird’s westward spread may have been the Indus Valley, where the city-states of the Harappan civilization carried on a lively trade with the Middle East more than 4,000 years ago. Archaeologists have recovered chicken bones from Lothal, once a great port on the west coast of India, raising the possibility that the birds could have been carried across to the Arabian Peninsula as cargo or provisions. By 2000 B.C., cuneiform tablets from Mesopotamia refer to “the bird of Meluhha,” the likely place name for the Indus Valley. That may or may not have been a chicken; Professor Piotr Steinkeller, a specialist in ancient Near Eastern texts at Harvard, says that it was certainly “some exotic bird that was unknown to Mesopotamia.” He believes that references to the “royal bird of Meluhha”—a phrase that shows up in texts three centuries later—most likely refer to the chicken.

Chickens arrived in Egypt some 250 years later, as fighting birds and additions to exotic menageries. Artistic depictions of the bird adorned royal tombs. Yet it would be another 1,000 years before the bird became a popular commodity among ordinary Egyptians. It was in that era that Egyptians mastered the technique of artificial incubation, which freed hens to put their time to better use by laying more eggs. This was no easy matter. Most chicken eggs will hatch in three weeks, but only if the temperature is kept constant at around 99 to 105 degrees Fahrenheit and the relative humidity stays close to 55 percent, increasing in the last few days of incubation. The eggs must also be turned three to five times a day, lest physical deformities result.

The Egyptians constructed vast incubation complexes made up of hundreds of “ovens.” Each oven was a large chamber, which was connected to a series of corridors and vents that allowed attendants to regulate the heat from fires fueled by straw and camel dung. The egg attendants kept their methods a secret from outsiders for centuries.

Around the Mediterranean, archaeological digs have uncovered chicken bones from about 800 B.C.. Chickens were a delicacy among the Romans, whose culinary innovations included the omelet and the practice of stuffing birds for cooking, although their recipes tended more toward mashed chicken brains than bread crumbs. Farmers began developing methods to fatten the birds—some used wheat bread soaked in wine, while others swore by a mixture of cumin seeds, barley and lizard fat. At one point, the authorities outlawed these practices. Out of concern about moral decay and the pursuit of excessive luxury in the Roman Republic, a law in 161 B.C. limited chicken consumption to one per meal—presumably for the whole table, not per individual—and only if the bird had not been overfed. The practical Roman cooks soon discovered that castrating roosters caused them to fatten on their own, and thus was born the creature we know as the capon.

But the chicken’s status in Europe appears to have diminished with the collapse of Rome. “It all goes downhill,” says Kevin MacDonald, a professor of archaeology at University College in London. “In the post-Roman period, the size of chickens returned to what it was during the Iron Age,” more than 1,000 years earlier. He speculates that the big, organized farms of Roman times—which were well suited to feeding numerous chickens and protecting them from predators—largely vanished. As the centuries went by, hardier fowls such as geese and partridge began to adorn medieval tables.

Europeans arriving in North America found a continent teeming with native turkeys and ducks for the plucking and eating. Some archaeologists believe that chickens were first introduced to the New World by Polynesians who reached the Pacific coast of South America a century or so before the voyages of Columbus. Well into the 20th century, chickens, although valued, particularly as a source of eggs, played a relatively minor role in the American diet and economy. Long after cattle and hogs had entered the industrial age of centralized, mechanized slaughterhouses, chicken production was still mostly a casual, local enterprise. The breakthrough that made today’s quarter-million-bird farms possible was the fortification of feed with antibiotics and vitamins, which allowed chickens to be raised indoors. Like most animals, chickens need sunlight to synthesize vitamin D on their own, and so up through the first decades of the 20th century, they typically spent their days wandering around the barnyard, pecking for food. Now they could be sheltered from weather and predators and fed a controlled diet in an environment designed to present the minimum of distractions from the essential business of eating. Factory farming represents the chicken’s final step in its transformation into a protein-producing commodity. Hens are packed so tightly into wire cages (less than half a square foot per bird) that they can’t spread their wings; as many as 20,000 to 30,000 broilers are crowded together in windowless buildings.

The result has been a vast national experiment in supply-side gastro-economics: Factory farms turning out increasing amounts of chicken have called forth an increasing demand. By the early 1990s, chicken had surpassed beef as Americans’ most popular meat (measured by consumption, that is, not opinion polls), with annual consumption running at around nine billion birds, or per capita, not counting the breading. Modern chickens are cogs in a system designed to convert grain into protein with staggering efficiency. It takes less than two pounds of feed to produce one pound of chicken (live weight), less than half the feed/weight ratio in 1945. By comparison, around seven pounds of feed are required to produce a pound of beef, while more than three pounds are needed to yield a pound of pork. Gary Balducci, a third-generation poultry farmer in Edgecomb, Maine, can turn a day-old chick into a five-pound broiler in six weeks, half the time it took his grandfather. And selective breeding has made the broilers so docile that even if chickens are given access to outdoor space—a marketing device that qualifies the resulting meat to be sold as “free-range”—they prefer hanging out at the mechanized trough, awaiting the next delivery of feed. “Chickens used to be great browsers,” says Balducci, “but ours can’t do that. All they want to do now is eat.”

It is hard to remember that these teeming, clucking, metabolizing and defecating hordes awaiting their turn in the fryer are the same animals worshiped in many parts of the ancient world for their fighting prowess and believed by the Romans to be in direct communication with Fate. A chicken bred for the demands of American supermarket shoppers presumably has lost whatever magical powers the breed once possessed. Western aid workers discovered this in Mali during a failed attempt to replace the scrawny native birds with imported Rhode Island Reds. According to tradition, the villagers divine the future by cutting the throat of a hen and then waiting to see in which direction the dying bird falls—left or right indicates a favorable response to the diviner’s question; straight forward means “no.” But the Rhode Island Red, weighted down by its disproportionately large breast, always fell straight forward, signifying nothing meaningful except the imminence of dinner.

Santería—the religion that grew up in Cuba with elements borrowed from Catholicism, native Carib culture and the Yoruba religion of West Africa—ritually sacrifices chickens, as well as guinea pigs, goats, sheep, turtles and other animals. Devotees of Santería were the petitioners in a 1993 First Amendment case, in which the Supreme Court unanimously overturned local ordinances banning animal sacrifice. The case pitted a Santería church, Lukumi Babalu Aye, and its priest, Ernesto Pichardo, against the city of Hialeah, Florida; many mainstream religious and civil-rights groups lined up with the church, while animal-rights proponents sided with the city. “Although the practice of animal sacrifice may seem abhorrent to some,” Justice Anthony Kennedy wrote in the decision, “religious beliefs need not be acceptable, logical, consistent or comprehensible to others in order to merit First Amendment protection.”

Chickens make wonderful pets, as breeders will tell you, especially if they think they could interest you in buying some chicks. They are as colorful as tropical fish but more affectionate, as cute as guinea pigs but better tasting, and, according to Jennifer Haughey, who raises chickens near Rhinebeck, New York, “far better mousers than our cats.”

What characteristics do chicken-owners value most? To Barbara Gardiner Whitacre, who raises five breeds of chickens in upstate New York, a leading criterion is egg color—the deep chocolate-brown eggs of her Welsummers, the jade green of the Ameraucana, the speckled olive of Ameraucana hens after a Welsummer rooster got loose and created an inadvertent cross. Also, hardiness, cuteness and a willingness to brood—to sit on a nest full of fertilized eggs until they hatch, contributing their own labor to the farm economy. The eggs don’t even have to be their own: As necessity dictates, Whitacre will substitute eggs laid by another hen, or even a duck. Unfortunately, these qualities are sometimes in conflict. She raises a breed called Silkies, with good looks to spare, bearing luxuriant feathers of an exceptional fluffiness. However, they also have blue skin and dark blue, almost black, meat and bones, which means they’re not the first thing you think of when company’s coming for dinner. Two years ago, Whitacre reluctantly sampled two Silkie roosters. “Of course, it was utterly delicious and tender, but blue-gray meat?” she recalls. “And the bones really are freakish-looking. So now if I can bring myself to use one for food, I generally use it in a dish with color: a nice coq au vin or something with tomatoes and thyme.” This is a prejudice not shared by some Asian cultures, which prize Silkies for food and medicinal purposes. Whitacre was surprised to see whole frozen Silkies, which each weigh only about a pound and a half, selling for more than $10 in her local Asian market.

Exotic and heritage breeds of chicken go for considerable sums of money—as much as $399 for a single day-old chick, as listed on the website of Greenfire Farms, where the names of the breeds are almost as beautiful as the birds themselves: the Cream Legbar, with its sky-blue eggs; the iridescent, flamboyantly tailed and wattled Sulmatler; the Jubilee Orpingtons in speckled brown and white, like a hillside on which the springtime sun has begun to melt the winter snow. The Silver Sussex, according to the website, looks “like a bird designed by Jackson Pollock during his black and silver period.” An advantage of many heritage breeds—an advantage for the chickens, that is—is that they spread their egg-laying careers over several years, unlike commercial varieties, bred for production, that are washed up in half that time.

And, for some chickens, the day comes when they are no longer wanted. That’s when the man of the house marches into the yard, puts the bird in the back seat and drives to Whitacre’s farm, leaving the chicken with her, whimpering that he just can’t bring himself to do what has to be done.

As he walks away, Whitacre sometimes says to herself, “I’m going to process eight birds today, mister. What’s wrong with you?”

Let us now praise chicken in all its extra-crispy glory! Chicken, the mascot of globalization, the universal symbol of middlebrow culinary aspiration! Chicken that has infiltrated the Caesar salad and made inroads on turkey in the club sandwich, that lurks under a blanket of pesto alongside a tangle of spaghetti and glistens with teriyaki sauce. Chicken that—marinated in yogurt and spices, grilled on a skewer and then set afloat in a mild, curry-flavored gravy—has become “a true British national dish,” on no less authority than former Foreign Secretary Robin Cook. In a 2001 address that has gone down in history as “the chicken tikka masala speech,” he chose that cuisine to symbolize his nation’s commitment to multiculturalism. The most frequently served dish in British restaurants, Cook said, was “a perfect illustration of the way Britain absorbs and adapts external influences. Chicken tikka is an Indian dish. The masala sauce was added to satisfy the desire of British people to have their meat served in gravy.” The great event took place in the early 1970s in an Indian restaurant in Glasgow, according to a Scottish MP who urged the European Union to grant the dish a “protected designation of origin.” This did not sit well with chefs in New Delhi, one of whom described chicken tikka masala as “an authentic Mughlai recipe prepared by our forefathers who were royal chefs in the Mughal period,” which covered roughly the 16th through 18th centuries.

If there’s an American counterpart to the tikka masala story, it might be General Tso’s chicken, which the New York Times has described as “the most famous Hunanese dish in the world.” That might come as news to chefs in Hunan, who apparently had never heard of it until the opening of China to the West in recent decades. The man generally credited with the idea of putting deep-fried chicken pieces in a hot chili sauce was the Hunan-born chef Peng Chang-kuei, who fled to Taiwan after the Communist revolution in 1949. He named the dish for a 19th-century military commander who led the suppression of the Taiping Rebellion, a largely forgotten conflict that claimed upwards of 20 million lives. Peng moved to New York in 1973 to open a restaurant that became a favorite of diplomats and began cooking his signature dish. Over the years it has evolved in response to American tastes to become sweeter, and in a kind of reverse cultural migration has now been adopted as a “traditional” dish by chefs and food writers in Hunan.

But increasingly, as foreign observers have noticed, “chicken” to the Chinese, at least those who live in the cities, means what’s served at KFC. Since the first drumstick was dipped into a fryer in Beijing in 1987, the chain has opened more than 3,000 branches around the country, and is now more profitable in China than in the United States. Numerous reasons have been advanced for this success, from the cleanliness of the restrooms to the alleged resemblance of Colonel Sanders to Confucius, but it apparently does not reflect a newfound Chinese appetite for the cuisine of the American mid-South. “You can find bone-in fried chicken there,” notes Mary Shelman, a Kentucky native and the head of the agribusiness program at Harvard Business School. “But it’s always dark meat, which the Chinese prefer, and it’s one menu item out of around 30, and it’s not the most popular.” The chain has thrived by offering the Chinese customers food they were already familiar with, including (depending on the region) noodles, rice and dumplings, along with chicken wraps, chicken patties and chicken wings, which are so popular, Shelman says, that the company periodically has to deny rumors it has a farm somewhere that raises six-winged chickens.

If it did, you could be sure, chicken hobbyists would be clamoring to buy them for their flocks, fancy restaurants would add them to their menus and food bloggers would be debating whether the first, second or third pair made the best Buffalo wings. The globe-spanning chicken is an epic story of evolutionary, agricultural and culinary success, outnumbering human beings on the planet by nearly three to one. Yes, we get to eat them, but we also feed them. And they provide—along with omelets, casseroles, fricassees, McNuggets and chicken-liver pâté—an answer to the question that every 6-year-old boy, visiting a natural history museum for the first time, has asked his parents: “What did a dinosaur taste like?”

It tasted like chicken.

Jerry Adler wrote about heirloom wheat farming in the December 2011 issue. Freelance writer Andrew Lawler is an occasional contributor to Smithsonian. Photographer Timothy Archibald is based in Northern California.