Authorities made what they called the largest cockfighting bust in U.S. history with the seizure of more than 5,000 roosters, hens and chicks from two training grounds. Agents found 4,400 chickens Saturday at a 7-acre compound in the Otay Mesa industrial area of San Diego. More than 2,500 birds were seized at the same place six years ago in what was believed to be the nation's largest bust. Hundreds more chickens were found this time at a second training ground nearby, officials said. More busts have resulted in arrests but none have produced more birds. Fifty people were issued misdemeanor citations, punishable by up to one year in jail and a $5,000 fine, and ordered to answer to cockfighting charges in early December, said Paul Levikow, a spokesman for the San Diego County District Attorney's office. If the defendants have a history of animal cruelty, they may be charged with felonies. Another 50 people are still being sought, authorities said. About 80 percent of the birds seized have been euthanized. The cockfighting operation was managed and patronized largely by Filipinos, and fights were staged in the San Diego area. Many birds were sent to the Philippines or Hawaii.