Bird flu has been identified at a poultry farms in Groningen and Overijssel, taking the total number of birds slaughtered since the outbreak began to nearly four million.

At least 49 poultry farms located within 10 kilometres of the affected farms are now now longer allowed to transport their birds and manure to avoid the risk of spreading the infection.

The current epidemic is the most serious in 20 years and over 70 farms nationwide have been affected so far. The Netherlands has some 1,700 poultry farms, half of which produce eggs.