If you're a chicken, Mamou, La., is one place you don't want to be, come Mardi Gras time.

In Mamou, Mardi Gras is celebrated Cajun style—no gaudy costume balls, fancy jazz bands, glittering floats or souvenirs. That's New Orleans stuff. Cajun Mardi Gras is about gumbo—about cooking up huge quantities of it and washing same down with even huger quantities of beer. But before the gumbo can be cooked, the ingredients must be fetched, which is where the chickens come in, poor things.

It is a few minutes before 8 on Mardi Gras morning in Mamou, a remote rough-hewn hamlet on a prairie planted alternately with rice, soybeans and winter rye, 180 miles northwest of Bourbon Street. In the American Legion Home, 104 men in snaggletoothed rubber masks or face paint, under a gallimaufry of caps and conical hats, are standing around impatiently, listening to 42-year-old Dale McGee explain the rules of the annual Mardi Gras "run." Soon they will spill outside, jump on horseback—one man to a horse, no exceptions—and ride off on a 17-mile hunt. Their mission will be to scare up chickens and other ingredients for the gumbo.

The chicken run follows a ritual of obscure origins that is believed to predate the Civil War. "It's a very mystical thing that is often misinterpreted by outsiders," says Paul Tate Jr., 38, a Mamou lawyer who is the festival's chief organizer. "Among the early settlers, one party animal just may have picked up a jug of 'shine and gone to the next town to share it with his neighbor and make a gumbo. The next year they may have hit seven houses." Discontinued during World War II, the run was revived in 1952 by Tate's father as part of a campaign to preserve Cajun music, which he introduced to the Newport Jazz Festival in 1964, and Cajun culture generally.

Custom calls for the riders to stop at houses en route and dance—the wilder the better—for the entertainment of each household. Music is provided by a hot fiddlin' Cajun band on a flatbed wagon that accompanies the horsemen. Each rider has paid $10 to participate, and in return each gets a hard-boiled egg for breakfast, boudin (a hearty Cajun pork sausage) for lunch and all the beer he can drink, which is plenty. Accompanying the riders will be two trucks loaded to the gunwales with 125 cases of beer, and there won't be any leftovers. To reciprocate for the lusty dancing, the people of each house are expected to donate spices and other ingredients for the grand gumbo, including one or more live chickens, which the riders must catch on foot.

The run, also by tradition, is for males only. "For the boys it's kind of a rite of passage," Tate says, and "too dangerous" for women. With all the beer consumed, it has also proven too dangerous for men who have a tendency to fall off their horses. "Bones can get broken," Tate concedes.

Speaking in French, the Cajuns' language, run Capitaine McGee is now reminding the riders that for their own good, given the ride's predilection for rowdiness, pistols and knives are défendu. "Let's ride!" younger riders shout. "Allons!" call those a bit older. And finally, shortly after 8, the group heads out, two by two. The bars have already been open for an hour, and the street is beginning to fill with revelers, who will spend their day downing fried chicken and beer in tune-up for the final feast.

The convoy's first stop is the home of George Lebeau, 64, just outside town. When Lebeau tosses a live red rooster into the air, two dozen men scramble after it, and one finally holds up the flapping bird in triumph. "He crowed this morning for the last time," says Lebeau philosophically as the caravan moves on.

Many homeowners have a more cautious approach. They have roped off their property and carry their chickens out to the curb to keep the visitors, two-legged as well as four-, from trampling their lawns. No matter what the reception, however, at each house the dust-caked men dance, sometimes right in their saddles. Roadside crowds cheer, and homeowners reach up to shake the riders' hands. And at each stop the musicians sing in French an old Cajun song whose lyrics translate—roughly—as: "Will you welcome this band of big drunks? Will you give us a little fat hen, so we can make a fat gumbo?"

At last the caravan swings through a cemetery and back into town. Between them, the 104 riders bear 32 chickens, two ducks and two guinea hens for the gumbo. At 3:30 p.m., the riders dismount one last time and boogie for the assembled, cheering horde, now 15,000 strong. Six years ago, there were only 4,000 visitors, indicating that, ready or not, tourism is creeping in on Mamou's Mardi Gras. Just as the procession is ending, the run suffers its only casualty when a man dressed as a wounded Confederate soldier falls off his horse.

He is taken to the hospital and, not long after, the only trace of the run's bounty is a pile of plucked feathers. By 9 o'clock, most of the gumbo is also gone. Those who can still move dance in costume till midnight, young and old, cheek to cheek. Spilled ice blankets Mamou's street like the leavings of a freak winter storm, but the joy of confusion, Paul Tate explains, is the real point. "It tends to distort reality," Tate says, "when you see a man who works in a business suit all week chasing chickens and falling off his horse." He says it happily. Tomorrow will be Lent, the start of the abstemious season.