LOUISVILLE, Ky. (AP) – Memo to KFC: Never underestimate the power of Oprah Winfrey.

Or the lure of a freebie.

A free grilled-chicken meal promotion touted by the popular talk show host has caused such a frenzy that a few stores ran out and the Louisville-based chain is asking customers to take a rain check for the deal.

“For the last day and a half, our restaurants have just been absolutely inundated,” KFC President Roger Eaton said in an interview Thursday with The Associated Press. “It’s just been overwhelming.”

Lines snaked outside some KFC restaurants and cars stacked up at drive-through windows as people waited to redeem the coupons available on Oprah.com for 24 hours this week, he said. The coupons also were available until late Wednesday on unthinkfc.com – a KFC Web site promoting the new grilled chicken.

Restaurants summoned extra help to keep pace with the crowds, yet some customers waited an hour and a half as the chain gave away millions of the meals Tuesday, Wednesday and part of Thursday.

Uncomfortable with the delays, the chain decided to ask people to wait longer for the meals – but with the hope of a more peaceful setting in which to eat them. Eaton said the company will mail coupons to customers in stages and throw in a free soft drink.

“The way we’re operating at the moment isn’t giving the experience that we’d like to give them,” he said.

Police in Greensboro, N.C., said the backup of vehicles heading to a KFC there created a hazard at the dinner hour Wednesday. A 911 caller complained of people arguing and said traffic was stopped, according to a 911 report. Authorities eventually blocked access to the restaurant, and many customers left without redeeming their coupons.

There were isolated reports across the country of customers becoming upset at KFC stores as they waited or as stores ran out of chicken on Tuesday and Wednesday.

The company said Thursday that it had received no reports of violence or arrests.

The rush began when the downloadable coupons were available on Oprah.com for 24 hours beginning Tuesday after Winfrey announced the promotion on her show. Each coupon promised two pieces of grilled chicken, two individual side orders and a biscuit.

A spokeswoman for Winfrey’s Harpo Productions in Chicago applauded the company’s decision to offer rain checks for the new meals, which KFC introduced three weeks ago as a healthier alternative to its popular staple, fried chicken.

“We feel this new plan is a great new way to accommodate the overwhelming interest,” the spokeswoman said.

The free-meal promotion was funded by KFC, a spokeswoman for the chain said.

Known for generosity, Winfrey has doled out impressive giveaways for her studio audiences, from books to cars, and her comments or support have caused distinct spikes in the popularity of everything from consumer goods to political candidates. She also has hosted a televised philanthropy competition, “Oprah’s Big Give,” where contestants help people in need.

KFC, a subsidiary of Louisville-based Yum Brands Inc., has backed its new Kentucky Grilled Chicken with an advertising blitz. The chain hopes to lure health-conscious customers with its grilled offering, which is lower in fat, calories and sodium than the chain’s fried chicken.

KFC has never had such a response to a special-meal offer, said KFC spokeswoman Laurie Schalow.

“It’s unprecedented in our more than 50 years,” she said. “It beats anything we’ve ever done.”

The chain would not say how much the giveaway cost because the expense was part of its much larger national marketing and promotions budget for the year.

“The relative costs of a day like yesterday are very small relative to the potential value of getting people to taste this product,” Eaton said. The draw, he said, was a mix of Winfrey’s star power, the lure of a free meal in tough times and curiosity about the new product.

It’s been a heady couple days for a chain that’s been struggling in the United States but growing furiously overseas, particularly in China.

“We’re getting people into the restaurants through this promotion who haven’t been to KFC for a very long time,” Eaton said. “We’re basically repositioning the brand through this exercise.”