US chicken producers, including Tyson Foods, Pilgrim's Pride and Perdue Farms, have offered a further five years of tariff protection for Mexico's chicken industry in order to prevent a trade dispute. Mexican farmers have been protesting in Mexico City because they say they cannot compete with US agribusinesses. Tariffs on more than 80 farm products, including chicken, ended on 1 January under the 1994 North American Free Trade Agreement.