I have recently been reading / researching about various chicken diseases and vaccines. Most places I read say if a chicken gets a disease like say infectious bronchitis (or many others just using this as an example) when they recover they are now carriers for life and any new chickens you add to the flock will then be exposed and get it, so there is a vaccine most appear to be live virus. Anyway the vaccine has to be readministerd every couple of months for life, causing them to create antibodies, how does this not in turn make them "carriers" and able to give the virus to new chickens? I don't understand how body produced antibodies from recovery from disease makes them "infectious" really carriers, but antibodies from continued or one time vaccine does not?
