A spokeswoman for the Department for Environment, Food and Rural Affairs (Defra) said the 1.78 million birds culled since the first outbreak on 5 November was a "small proportion" of the industry's total production, which is about 20 million birds a week.
At the beginning of the worst outbreak of bird flu, 3.2 million birds were culled between October 2021 and September 2022.
One of those farmers affected in 2021 was Lucy Sanderson, from North Yorkshire, who says people are not aware of the mental health impact culling birds had on farmers.
"It was awful. I cried for a week - and I thought I was a strong person," she said.
"As well as losing my job, my income, my everyday life, I also ruined my staff's lives as I had to make them redundant. The knock-on effect was huge.
"I am terrified of it returning."