Avian flu
The Department for the Environment, Food and Rural Affairs said the H5 strain was found in turkeys near Diss on the Norfolk and Suffolk border.
The site also houses ducks and geese and all the birds will be slaughtered.
A 3km protection zone and a 10km surveillance zone are being set up.
Preliminary tests showed the turkeys had the H5 strain of bird flu, but it is not yet known whether it is a highly pathogenic form of the disease.
All birds are being slaughtered at the premises, and Defra said it was consulting on what further measures may be needed.
- Reporting dead birds
How to report dead birds which may have avian influenza.
