It is because this past year has been a very severe avian flu outbreak. A record 58 million poultry have been affected in the US. The previous deadliest US outbreak in 2014-2015 had 50 million killed. This also contributed to the high turkey prices last Thanksgiving as both chicken and turkey stocks have been affected. 47 states have domestic poultry affected, but infected wild birds have been detected in all 50 states.
This is the first time since 2016 HPAI A(H5N1) viruses have been circulating in the US.
Typically avian flu subsides in the summer, but this outbreak persisted. Hopefully it gets under control by next summer.