Welp, the α2:3 receptors found thorough out the avian respiratory tract are also found thorough out their digestive tract…This is why factory farms using chicken litter (scrap bird feed + bird feathers + bird shit) to feed cattle has led to the first ever cases of avian flu in cows. If cows have it, won’t be long before pigs get it, and they’re the perfect mixing vessels as they have both α2:3 and α2:6 in their respiratory tract. This is the ideal setup for influenza’s classic reassortment mutation, which could easily lead to another pandemic. But, maybe this was your point lol