WellReadReviews, it depends on what you want to do with the flock. Once recovered from most of the respiratory viruses, the chicken becomes a carrier for the rest of its life. So if you reintroduce it to the flock (or even if the flock already had a carrier) you're going to have an infective flock. If you just use your chickens for pets or small-scale egg production, some people choose to just live with it.
Not all of these diseases have a high mortality rate, but I believe they do all affect productivity, at least while the illness is active. And if you chose to keep an infective flock, you couldn't ethically sell chickens to an unsuspecting customer or take them to a show where they can infect other birds. Any birds that you bring in which aren't already vaccinated for the particular strain of whatever you have, have a high chance of catching it themselves.
And since some of the vectors seem to be wild animals, it's possible that an infected flock could pass it on to neighboring flocks. That may be how I got it, for all I know. I live in an area with high commercial poultry production, and that was one of the factors in my deciding to cull the entire flock. Even though there are plenty of home flocks around here that probably don't care about the commercial producers, I do care, and don't want to have a reservoir of the disease at my house.
I also wanted to show birds, and to be able to bring new birds in. I didn't want to deal with illness the rest of my life either. So, the choice to cull. All birds coming in will be vaccinated for ILT, but of course, there are plenty of other respiratory diseases to which they will still be susceptible. It's a calculated risk for me, but at least I'm controlling the factors that are reasonably controllable.
The lime link was interesting. I think I'll lime the soil and plow it in to help the UV light along in the disinfection process.
