Salmonella in indoor and outdoor chicken housing 

This paper may be of interest to some.  Basically, the authors compared Salmonella levels in outdoor vs. indoor housing for chickens. The main push behind this appears to be the growing trend for having more outdoor housing for chickens and the question of whether or not that leads to higher levels of pathogens.

See Occurrence of Salmonella spp.: a comparison between indoor and outdoor housing of broilers and laying hens | Acta Veterinaria Scandinavica | Full Text

by Martin Wierup, Helene Wahlström, Elina Lahti, Helena Eriksson, Désirée S. Jansson, Åsa Odelros and Linda Ernholm