Hen or manager who is responsible for dust and ammonia in the stable?
According to EU and national regulations in Germany layers are kept not any longer in cages. There are alternatives on the market. An assessment of different keeping/management systems for laying hens with regard to individuals health and environmental protection is required. One open question concerned is the relevance of airborne dust and ammonia. This paper deals with investigations running in two systems for keeping laying hens aviary and German small group housing system regarding dust and ammonia concentrations inside the stable and their emission flows. The systems vary in size, stocking density and management. First data on airborne exposure indicate differences between the housing systems investigated. The ammonia concentrations reach from less than 1 ppm to more than 20 ppm and PM4 from 0,1 to 2 mg/m³. Ammonia produced essentially by the birds faeces. Manure management is one of the most important factors to reduce the concentration of ammonia. Dust emissions are mainly caused by birds activity which can be influenced by e.g. the light programme