This seemed counter-intuitive to me, and in particular I recalled a scene in the documentary Food Inc where an organic poultry farmer extolled how much cleaner

This seemed counter-intuitive to me, and in particular I recalled a scene in the documentary Food Inc where an organic poultry farmer extolled how much cleaner it was to be processing meat in the open air rather than in an environment mediated by chemical sterilization. However, it does seem like this is a thing, in particular there was a Swedish study in 2009 that was referenced several times in media coverage and I can find no follow-up or rebuttal to: https://www.sciencedaily.com/releases/2009/01/090114200003.htm https://www.sciencedaily.com/releases/2009/01/090114200003.h... And then in 2014, an industry-focused article on how to mitigate some of these effects, in particular rodents: https://www.thepoultrysite.com/articles/range-management-for-disease-control-guidelines-to-protect-your-freerange-flock-from-exotic-disease https://www.thepoultrysite.com/articles/range-management-for...