Cage Versus Noncage Laying-Hen Housings: Respiratory Exposures

The objective of this study was to compare the personal respiratory exposures of poultry workers in three different types of layer housing under commercial production conditions. Workers were randomly assigned to each of conventional cage, enriched cage, and aviary barns in a crossover repeated-measures design for three observation periods over the hens' lifetime. Inhalable and fine particulate matter (PM) and endotoxin in both size fractions were assessed by personal and area samplers over the work shift. Concentrations of inhalable PM, PM2.5 (PM with an aerodynamic diameter <2.5 μm), and endotoxin in both size fractions were higher in aviary than either the conventional or enriched barns. Geometric means (95% confidence intervals [CIs]) of inhalable PM and endotoxin for the aviary, conventional, and enriched barns were 8.9 (6.8-11.5) mg/m(3) and 7517.9 (5403.2-10,460.2) EU/m(3), 3.7 (2.8-4.8) mg/m(3) and 1655.7 (1144.6-2395.2) EU/m(3), 2.4 (1.8-3.3) mg/m(3) and 1404.8 (983.3-2007.0) EU/m(3), respectively. Area samplers recorded a lower mean inhalable PM concentration and higher PM2.5 concentration than personal samplers. Ammonia concentrations were low throughout three monitoring seasons. These findings show that the aviary barns pose higher respiratory exposures to poultry workers than either conventional or enriched barns.