CHICAGO, May 17 (UPI) -- Some of the food industry's biggest players say they have reduced their participation at Saturday's National Restaurant Association trade show in Chicago.

In what could be seen as a sign of tough times in the industry, two of the nation's biggest chicken producers, Perdue Farms Co. and Tyson Foods Inc. (NYSE:TSN), have cut back on their activities at the annual trade show. French fry maker McCain Foods Ltd., abruptly pulled out of the gathering, The Chicago Tribune reported.

The newspaper says restaurant show organizers have been able fill McCain's floor space at Chicago's McCormick Place convention center, and that the event is bigger, selling out for the third straight year. But because of a slump in the restaurant industry, keeping exhibitors has become a challenge.

"Because of the challenging economic climate we do have to sell the benefits of the show to exhibitors and attendees," Greg Kirrish, the restaurant show's vice president of sales and marketing, told the Tribune.

In an effort to contain costs, Perdue Farms canceled a party Saturday at a Chicago Williams-Sonoma store.