Highly pathogenic avian influenza H5N1 has been found at a premises near Eton, Windsor and Maidenhead, Berkshire. Following a risk assessment a 3km Captive Bird (Monitoring) Controlled Zone has been put in place. More information is available on GOV.UK: https://www.gov.uk/bird-flu
Definitive requirements are set out in the published declarations for each disease control zone currently in force. For further information see the following:
The ‘Cases and disease control zones’ section on GOV.UK: https://www.gov.uk/guidance/avian-influenza-bird-flu-cases-and-disease-control-zones-in-england#cases-and-disease-control-zones
You can also check if specific areas are in a zone by using the interactive map available on GOV.UK: https://defra.maps.arcgis.com/apps/webappviewer/index.html?id=8cb1883eda5547c6b91b5d5e6aeba90d