Investigations are continuing in a bid to trace the source of a bird flu outbreak which prompted the cull of 8,000 Gressingham ducks at a farm near Attleborough.
Animal health experts are working at Homelea Farm in Great Ellingham to assess "all possible routes of spread" both into and out of the site, where the avian influenza virus was confirmed on Saturday.
The farm is run by Green Label Poultry which supplies Suffolk-based Gressingham Foods, the UK's biggest supplier of duck to supermarkets.
It is the third bird flu outbreak in Norfolk this month, and within 3km of the first confirmed case at North Farm in Snetterton - but government officials have not yet confirmed if there is any link between the two cases.
A Defra spokesman said: "A detailed veterinary investigation is ongoing.
"All possible routes of spread onto and onward transmission from the infected premise to other poultry and captive birds are being followed up to protect animal health from further avian influenza infection – this includes tracing all products from the infected premises."
In a statement released on Monday, Gressingham Foods said: "There have been no movements of eggs, birds or other materials off the premises since December 3.
"The welfare of our birds is an absolute priority, and we work to the highest standards in hygiene, bio-security and animal welfare across all our farms."
Defra has enforced a 3km Protection Zone and 10km Surveillance Zone around the premises, including increased biosecurity requirements and restrictions on the movement of poultry, eggs, meat and carcases to limit the risk of the disease spreading.
In response to the rising number of cases across the country, all poultry - including free-range and back-yard flocks - are also required to be kept indoors under a mandatory housing order announced by chief vets in a further effort to prevent outbreaks.
Public Health England advises that the risk to public health from the virus is very low and the Food Standards Agency advises that avian influenzas pose a very low food safety risk for UK consumers. Properly cooked poultry and poultry products, including eggs, are safe to eat.
- Bird flu is a notifiable animal disease. Poultry keepers and members of the public should report dead wild birds to the Defra helpline on 03459 33 55 77 and keepers must report suspicion of disease to the APHA on 03000 200 301.
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