Avian influenza H5N8 (pathogenicity to be confirmed) was confirmed in laying chickens at a premises near Redcar, Redcar & Cleveland on 6 February.
Defra said it had acted quickly to cull affected birds and to introduce movement restrictions to limit the risk of the disease spreading.
All poultry keepers are currently required to house their birds to reduce the risk of AI spreading. The housing order came into force on 14 December.
A joint statement from Great Britain’s three Chief Veterinary Officers said: “We have taken swift action to limit the spread of the disease and have introduced a legal requirement for all poultry and captive bird keepers to keep their birds housed or otherwise separate from wild birds.”