(Reuters) – The world’s largest chicken breeder has discovered that a key breed of rooster has a genetic issue that is reducing its fertility, adding to problems constraining U.S. poultry production and raising prices at a time when beef and pork prices are already at record highs. The breed, Aviagen Group’s standard Ross male, is sire through its offspring to as much as 25 percent of the nation’s chickens raised for slaughter, said Aviagen spokeswoman Marla Robinson. Sanderson Farms, the third-largest U.S. poultry producer and one of Aviagen’s largest customers, said it and Aviagen systematically ruled out other possible causes for a decline in fertility before determining a genetic issue was at the root of the problem. (via Exclusive: Roosters’ fertility problem hits U.S. chicken supply, lifts prices | Reuters)