The Department for Environment, Food and Rural Affairs said the site was within a surveillance zone set up after the disease was confirmed on a nearby farm earlier this month.
Two outbreaks of the deadly H5N1 strain of bird flu have been confirmed in eastern England, and thousands of turkeys, ducks and geese have been killed as a precaution.
Bird flu's return to Britain weeks before the Christmas holidays has been another blow to Britain's farmers, already struggling after livestock herds were hit earlier this year by foot-and-mouth and bluetongue diseases.
Millions of birds worldwide have died or been slaughtered since late 2003, when H5N1 began ravaging Asian poultry stocks. It has killed at least 206 people worldwide since 2003.
Experts believe most victims were probably infected through direct contact with sick birds.
Bird flu is difficult for humans to catch, but experts fear it could mutate into a form that spreads easily among people, potentially sparking a flu pandemic.