All premises that keep 50 or more birds of designated poultry species are required to register on the Great Britain Poultry Register (GBPR). As of 5 January 2007, there were around 17,000 such premises registered employing around 61,000 poultry workers.
Further information about the number of poultry workers eligible for receiving seasonal influenza vaccination is contained in the departmental guidance on the implementation of a seasonal flu vaccination programme for poultry workers available at:
www.dh.gov.uk/en/Policyandguidance/Healthandsocial caretopics/Flu/DH_063506