The only thing I can add to this is that some agencies have at least been clear that even after vaccination, people should still be social distancing and wearin

The only thing I can add to this is that some agencies have at least been clear that even after vaccination, people should still be social distancing and wearing a mask. I realize that is far looser in the US, but here in Canada, it has not been loosened in this way. With birds, you won't be masking them or keeping them at distances. So their ability to spread disease is significantly higher. Our take on this up here at least is that you have to do everything to get these numbers down. We recognize that you can still catch and spread the virus even if you've been vaccinated. Apparently you'll get less ill if you are vaccinated and catch it, but you still have to avoid infecting people who have not yet been fully vaccinated - something birds don't have as much control over.