Two more poultry farms in England have become infected with a form of bird flu. 

Britain's Department for Environment, Food and Rural Affairs said initial laboratory results suggested the farms in Norfolk had been affected by the less serious H7 strain of the virus. 

A restricted zone had been put in place around the infected farms and the flocks involved would be slaughtered. 

The Chief Veterinary Officer, Debbie Reynolds, said the farms were close to a farm where about 35,000 chickens were culled following an outbreak of bird flu last week.