The Canadian Food Inspection Agency says the virus was confirmed on Thursday at an Abbotsford farm and it affects about 7,000 chickens.
That means some 180,800 chickens and turkeys are now either dead or set to be euthanized.
The outbreak began last week, when poultry at two farms in the Fraser Valley tested positive for the H5N2 strain of the disease.
Earlier this week, the Canadian Food Inspection Agency announced a control zone covering the southern half of B.C., where restrictions have been placed on the movement of poultry.
Eight countries have placed restrictions on B.C. poultry and poultry products.
On Wednesday Singapore joined the list of the United States, Mexico, South Africa, Japan, Taiwan, Hong Kong and South Korea.