Creating resistance to avian influenza infection through genome editing of the ANP32 gene family: <a href="https://www.nature.com/articles/s41467-023-41476-3" rel="nofollow noreferrer">https://www.nature.com/articles/s41467-023-41476-3</a><p>"These mutations unexpectedly allowed the usually host-restricted avian influenza polymerase to use the shorter human ANP32A and B and thus partially adapted the viral polymerase for replication in mammals. Although unintended, this consequence clearly indicates the importance of a robust genome editing strategy and subsequent appraisal that includes challenge with multiple avian influenza genotypes at non-physiological exposure levels to rule out the opportunity for adaptive viral evolution."
I doubt these chickens would be used in large scale farming due to various concerns, but as a last line defense of the US flu vaccine manufacturing capability it might be worth it. Each standard flu vaccine dose takes about one fertilized egg worth of cultured virus to produce, so you need a lot of chickens around to have that capability. These genetically modified chickens could be stored in secure Strategic National Stockpile facilities in large numbers to prevent major production problems in the event of an avian influenza pandemic.