DES MOINES, Iowa (AP) — Scientists have developed a vaccine strain that is 100 percent effective in protecting chickens from bird flu and testing is underway to see if it protects turkeys. U.S. Agriculture Secretary Tom Vilsack told the House Agriculture Committee on Wednesday that the agency plans to quickly license the vaccine for widespread production. The USDA is seeking federal funding to stockpile the vaccine nationally. The drug targets the H5N2 virus that killed 48 million birds in 15 states this spring. Scientists believe the virus was spread by droppings of wild birds migrating north this spring. They're concerned it could return this fall when birds fly south for the winter or again next spring.