There is a window of relief for British Columbia farmers from the devastating waves of avian flu, leaving them to assess the toll of outbreaks spanning more than three years that saw millions of birds culled at hundreds of farms.

Farmers and scientists also worry what the next migration of wild birds will bring this year.

Some farmers have moved their operations outside British Columbia's Fraser Valley or exited the industry altogether since the highly pathogenic H5N1 avian flu began circulating,…