Bird flu has been confirmed at a large, commercial poultry site, according to the Department for Environment Food and Rural Affairs (Defra).
It says a 3km (1.9 mile) protection zone and a further 10km (6.2 mile) surveillance zone have been declared around premises, which is near the village of Ashcott, in Somerset.
Defra said the highly pathogenic avian influenza (HPAI) H5N1 had been confirmed on 29 November.
It added that all the poultry on the premises would be humanely culled.
The 10km surveillance area includes Glastonbury, Street and numerous villages.
The introduction of the disease control zone means by law people must follow strict biosecurity and hygiene rules to avoid any spread.
These include not moving poultry without a licence.
