The Associated Press reports that a federal judge granted class action status to a lawsuit that contends Tyson Foods Inc., depressed wages by hiring illegal immigrants at eight plants in Tennessee, Alabama, Indiana, Missouri, Texas and Virginia. A federal jury in March 2003 acquitted the company and three former managers of conspiring to hire illegal immigrants from Mexico and Central America for low-wage production jobs to boost profits. Two former Tyson managers who made plea deals were each sentenced to one year of probation. The acquittal dealt a setback to the government''s strategy of enforcing immigration laws by going after big business. Prosecutors in the Tyson case relied mostly on tapes of secretly recorded conversations between undercover agents who posed as smugglers and transporters of immigrants and former managers at Tyson poultry plants. Tyson attorneys argued successfully that if the company hired illegal workers, it was because of the huge underground market for phony immigration papers and the government''s flawed system of screening immigrants. Agents testified that they delivered 136 illegal immigrants from Mexico and Central America for Tyson employment. Other testimony said the company tried to shield itself by using temporary employment agencies to find workers, mostly illegal immigrants. Before the case went to trial, four former employees at Tyson''s Shelbyville plant sued. The eight Tyson plants named in the suit are at Shelbyville; Corydon, Ind.; Gadsden, Ala., Blountsville, Ala., Ashland, Ala.; Sedalia, Mo.; Center, Texas and Glen Allen, Va.