Assessment of farm-level biosecurity measures after an outbreak of avian influenza in the United Kingdom.

During Avian Influenza outbreaks in England, the 'AI Order' states that a poultry keeper may be required to keep domestic birds separate from wild birds. This study aimed to assess a) how effectively this was done and b) the negative impact this had for bird owners and animal welfare during the November 2007 Highly Pathogenic Avian Influenza (HPAI) outbreak in Suffolk, UK. A voluntary questionnaire was posted to holdings (n=296) that were within 10 km of an infected premises; these holdings were required to separate domestic and wild birds where possible. Holdings were identified during outbreak investigations conducted by the authorities. Holdings of all sizes were included. A sample of holdings received a follow-up visit or telephone call to validate the questionnaire (n=29). From the 38% of eligible holdings that responded, 13% (95% CI 7-22%) left their birds outdoors throughout the outbreak. If game birds were excluded, 9% (CI 4-17%) of holdings did not house their birds. Major cost and welfare problems were rare; however, there were exceptions. Enforced housing was often relaxed before a minor welfare problem deteriorated. Contact between wild and domestic birds was greatly reduced during the outbreak, resulting in a reduced probability of HPAI transmission via wild birds for most, but not all, holdings.