DES MOINES — Stay calm and cook your eggs.That’s the advice from a trio on the front lines of the battle to contain and defeat avian flu in Iowa poultry flocks.The 6-week-old avian flu outbreak that has claimed 45 percent of the laying hens in Iowa, the nation’s No. 1 egg producer, will have an impact on the state’s economy, egg and poultry producers and consumers’ pocketbooks, but doesn’t pose a health threat to Iowans, according to Bill Northey, Iowa secretary of agriculture; Hongwei Xin, who directs Iowa State University’s Egg Industry Center; and Randy Olson, director of the Iowa Poultry Association.“If you prepare the eggs properly, hit that certain temperature, say 165 degrees, then that should kill the virus,” Xin said during recording Friday of Iowa Public Television’s “Iowa Press.”“Properly prepare the product, whether it is turkey meat or eggs, then you should be OK to eat.”As of Friday afternoon, there have been 64 cases of bird flu reported in Iowa, according to the Department of Agriculture and Land Stewardship.