South Korean authorities have just confirmed that breeding chickens in Chonan, 55 miles south of the capital Seoul, were infected with the highly pathogenic H5N1 bird flu virus strain. This is the fifth outbreak in the country during the last three months. Preparations are underway to cull over one-quarter of a million birds within half-a-kilometer of the farm, say officials from the Ministry of Agriculture. Measures to stem the spread of the virus also include a total restriction in the movement of birds and eggs within a 10 kilometer radius of the infected area.