Barns are more remote than "sterile environments" which usually consist of the more populated City environments. Human disease typically comes from OTHER humans, not random places of their environment. Of course, you can still get sick without receiving the infection from someone, but simply stating that dirty barns are healthier is incredibly misleading.

What were the specifics of that study? Was it a controlled experiment or more like an account of various cases compiled together? It makes a difference.

Of course, you state this evidence simply to prove your point, not to verify its authenticity. Therefore, it wouldn't matter what I said. Except, you can create evidence to prove whatever you want. The only way to definitively decide what's healthier is through a more rigorous, detailed experiment. And even then...??