Air quality and hen health status in three types of commercial laying hen houses

Environmental conditions and bird health are important elements in assessment of animal welfare for laying hen housing systems, but limited information is available comparing different types of systems. Three types of laying hen houses - caged high-rise, caged manure-belt, and cage-free floor-raised - were monitored for temperature, relative humidity, carbon dioxide, and atmospheric ammonia during winter and summer conditions in Iowa. During winter conditions, temperature and ammonia concentrations were maintained at a more comfortable level for the caged facilities. During summer conditions, temperature showed the least rise above ambient for the cage-free facilities, and ammonia was maintained at similar levels for all housing types. Assessment of hen health status revealed differences in pathogen frequency between housing systems for winter and summer, but not conclusively in favor of one system over another. The results of this observational study indicate that each system may offer benefits during specific weather conditions. Further monitoring to quantify the benefits of each system should be completed.