The big publicly traded poultry companies – Tyson Foods, Sanderson Farms and Pilgrim’s Pride Corp. – have all seen their stock prices tumble in the past 52 weeks. Sanderson shares have fallen 21%, Tyson shares 68%, and shares of Pilgrim’s Pride have plummeted 99%. On the consumption side people are dining out less often, especially at casual sit-down restaurants where chicken often is a menu staple. Sales to supermarkets and other retailers haven’t grown enough to offset the lost business, experts say.