Bird or manager - who is liable for dust and ammonia in layers stables?

According to EU and national regulations in Germany layers are kept not any longer in cages. Alternatives are placed 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 gives a first impression of investigations running in two different systems for laying hens - aviary and German small group system - with view to dust and ammonia concentration 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 1ppm to more than 20 ppm and PM4 from 0,1 mg/m³ to 2 mg/m³. Ammonia is produced by the birds’ faeces. Manure management is one of the most important factors. Dust emissions are mainly caused by birds’ activity, which can be influenced by e.g. the light programme.