''No one in the corporate offices knew of this,'' Mr. Levine said in a telephone interview.

The government said that a 30-month investigation, led by the Immigration and Naturalization Service, found that about 15 Tyson plants in 9 states were involved in a conspiracy from about 1994 to 2001.

Along with the company, the government charged two Tyson executives, Robert Hash, a vice president in Springdale, Ark., and Gerald Lankford, a human resources manager, with defrauding the government by conspiring to recruit Mexican and Central American immigrants along the United States border with Mexico and by helping them obtain illegal documents like fraudulent Social Security cards.

Mr. Hash and Mr. Lankford, who supervised Tyson poultry plants, including one in Shelbyville, Tenn., where the investigation was centered, were unavailable for comment yesterday. Tyson said both had been placed on administrative leave, pending a decision.

The indictment said that, to meet production and profit goals, Tyson officials would contact local smugglers near its plants to get more workers.

The recruiters would contact with smugglers in Mexico, who would round up people willing to work for Tyson, the indictment said. Tyson officials would then arrange to meet the workers along the border, the government said, and transport them to meat processing plants.

The government said that Amador Anchondo-Rascon, a Mexican resident and United States citizen who once worked in the Tyson plant in Shelbyville, was a recruiter and smuggler of illegal workers and that he arranged transportation and trafficked in illegal documents. Mr. Anchondo-Rascon, who the government said referred to himself as the ''Jefe de Jefes,'' or the boss of the bosses, was a primary contact for Tyson officials seeking new workers, the authorities said. He was named an unindicted co-conspirator in the case but the government did not say why.

Mr. Anchondo-Rascon arranged to have illegal immigrants picked up just across the Mexican border, the government said, and to have them transported to Tennessee, Virginia, Indiana, Missouri, Arkansas and elsewhere.