killing 100 000 chickens cause one had the flu isnt gonna do much, the thing with bacteria is that they are sneaky little buggers and they will always find a way to survive.
The flu is a virus (as you also mentioned in a previous post). Bacteria (or their spores) can survive without a host for a very long time indeed. But I'm not sure about virussen. I know HIV can't survive without a host very long. I don't know how long the flu virus can survive without a host. But killing the chickens will ofcourse enormously reduce the chance people get infected.