Companies producing more than 90% of America’s chicken have conspired to depress wages for a largely immigrant work force in some of the nation’s most dangerous jobs, according to a lawsuit.

The case filed last week is mostly based on interviews with former employees, and claims the conspiracy among 18 companies, their subsidiaries and affiliates and two consulting firms continues until today. It was filed on behalf of three former workers, but seeks class-action status for hundreds of thousands, many with limited language skills and few other prospects for employment.

Since 2009, leaders of the firms’ human resources and compensation departments have held annual secret meetings at a Destin, Florida, hotel to discuss pay and benefits for line and maintenance workers at about 200 plants, according to the complaint in Baltimore federal court. Using consulting agencies as intermediaries, the suit says, they share detailed wage information. Plant managers also cooperate, for example calling each other when one announces an expansion to find out what new positions will pay, it says.