After a Dutch vet died last week after being exposed to bird flu, more than 700,000 chickens have been slaughtered by Belgian authorities. The birds had been reared near the Belgian border with the Netherlands. They were kept on at least 28 different sites near the three farms where the disease was identified last week. The national food safety authority, Afsca, commented: "We are on a heightened state of vigilance to ensure no other outbreaks occur in Belgium".