MAMOU, La.—The teenage boy is covered in mud, literally from head to toe. After wading through a flooded rice field to catch a wayward chicken, he wipes mud from his eyes.

"I almost had him," he says to a friend with a shake of his head, and shrinks back to his horse.

Welcome to the home of the Cajun Mardi Gras, where men dance on horseback, chickens are their prey, and frivolity is the rule.

Mamou is a small town plopped in the middle of farming fields in the center of Cajun country, three hours northwest of the state's most famous Mardi Gras reveling town, New Orleans.

There is one high school here, one stop light and no Wal-Mart. The population of 3,500 is generally divided into halves—white or black, Baptist or Catholic, young and old. It is also my hometown.

Mamou has a few claims to fame. Fred's Lounge, a bar in the center of town where Cajun musicians gather every Saturday morning for a live radio music show and dance, is one. There's also the annual Cajun Music Festival—a given for a town claiming to be the "Cajun Music Capital of the World."

It birthed Steve Riley and the Mamou Playboys, an internationally renowned Cajun music band that often returns home to play the street dance the night before Mardi Gras here. And Chicago Bulls player Chris Duhon was born here.

But there is nothing more famous here than the Courir de Mardi Gras.

In the courir, which literally means "the run," on Mardi Gras day men dress in costume and ride horseback from home to home in the countryside, "collecting" ingredients for the town gumbo—and by collecting, I mean chasing after live chickens and catching them with their bare hands.

The tradition started in the 1800s in rural south Louisiana, but was suspended during the Civil War and in World War II. It was revived in Mamou in the 1950s and is practiced in several other towns around the area.

Local historians say the idea of the rural run was a way for the community to share in a pre-Lenten celebration, especially when times were difficult and the ingredients for a large gumbo hard to come by. It has evolved, however, into a sort of Cajun bar mitzvah. Teenage boys, usually around age 16, run the Mardi Gras as an informal entry into manhood.

While thousands of tourists flock to Mamou each year to enjoy the Cajun music and four-day festival in town (this year Feb. 2-5), few venture out into the rural prairies to follow the Mardi Gras riders . But they should—that is where the area's truly unique traditions can be found.

Mamou sticks to old, some would say arcane, rules. It is all-male and unofficially segregated (there is an all-black Mardi Gras group that runs a different route on the same day), and requires all riders to be in costume.

When I went last year, I brought my boyfriend, my roommate and her boyfriend, Chicagoans who had never seen the festival, and convinced the men to ride.

We arrived at the meeting hall just about 7 a.m. and joined a line of men and teenage boys, all bleary-eyed and anxious. Some had not slept at all since the previous night's fais-do-do, or street dance. Most were dressed in the traditional Mamou Mardi Gras costume—colorful long-sleeved shirts and pants, accented in fabric fringes, with required masks. Some were wearing the capuchon as well, a tall, pointed dunce-like cap decorated to match their costumes. (One teen, upon finding out that he must have a hat, ran outside to grab an empty Miller Lite box and placed it on his head.)

Before they can ride, their costumes are inspected by the capitaines, men who have run the Mardi Gras for many years, and serve as the chaperons for the day. The capitaines do not drink and are not masked, though they wear purple, green and gold capes, the colors of Mardi Gras.

The riders pay $25 and sign a liability waiver, which reads, in part, that they are aware there will be large animals involved in the day's events, and they will not sue for any injuries they might incur.

After a large crowd of riders gathered, a capitaine asked if I was signing up a rider (parents can sign up their underage teens). When I said I was not, I was promptly told to leave the room. "No women allowed," he bellowed with a snicker.

The doors closed, and the riders were given a few rules, which my friends divulged later in the day. No talking to women ("This is a man's day!"), and no knives. That's it.