Fresh outbreaks of avian flu have been reported in South Korea this week.
The news marks the first new cases of bird flu in poultry for six weeks.
The outbreak, on a single farm north of Seoul, have led to fresh slaughterings of the 20,000 chickens on the farm, and a further 400,000 within a three kilometre radius.
South Korea has now had 19 farms hit by the disease, but the latest outbreak, the first since February 5, has dashed hopes the country had the disease under control.