Bird flu was discovered at a poultry farm in the central Dutch province of Flevoland, the Ministry of Agriculture said Friday. It said the virus discovered was a mild variant. The farm\'s 47,000 chickens were slaughtered to prevent the virus turning into a contagious and deadly variant. It remains uncertain whether the chickens were infected with the high or low pathologene H7 variant. The low pathologene version can mutate into a high pathologen, which is extremely transmittable. Poultry from other farms in a zone of three kilometres of the contaminated farm will be tested. A prohibition of transport for poultry, eggs and poultry manure has been set.