I suppose when all of the flocks are dead from HPAI (highly pathogenic avian influenza), they have a sort of “herd immunity.” At least, they won’t be getting sick or spreading disease any longer.
The notion that you should catch a dangerous disease in order to be immune from it in the future is ludicrous and illogical. The whole purpose of vaccination is to give you immunity BEFORE you are exposed, so that you have as much protection as possible whenever you are exposed to the real pathogen. Should you wait until after you have a car crash to start wearing your seatbelt?
Also, herd immunity refers to a situation in which enough people are vaccinated within a short enough period of time that the disease has nowhere to go to infect new people. For a disease like Covid or measles, around 95% of people need to be vaccinated to achieve herd immunity.
Flu vaccines are based on last year’s viruses.
Like the cops showing up after the robbers have left.