Only healthy laying hens are capable of producing an average of 280 eggs in 1 year of exploitation. Production of consume eggs takes place in intensive housing systems where the laying hens are still mainly kept in cages under controlled conditions. Technical infrastructure and hygiene quality do not guarantee a production atmosphere completely free from pollutants, including potential pathological risk factors. Laying hens and farm workers are exposed to large quantities of bioaerosols in henhouses. Bioaerosols represent a mixture of different biological particles which can, under certain circumstances, cause health and welfare problems in animals. The most important components are dust, microorganisms, and microbial constituents, such as endotoxins. Because of this complexity, numerous measurements and the application of different methods is necessary in order to assess the health effects of bioaerosols and define future research goals. Therefore, a literature review was carried out on bioaerosol composition and the amounts found in laying hen houses. This paper deals with dust and endotoxins: their sources, concentrations, and methods of determination. The wide range of particle concentrations is strongly influenced by the use of different sampling and evaluation methods-and different application and handling of the same method-as well as sampling time, season, and the type of laying henhouse. This paper recommends establishing occupational health limits on bioaerosols for animals and animal caretakers in laying hen dwellings.

Only healthy laying hens are capable of producing an average of 280 eggs in 1 year of exploitation. Production of consume eggs takes place in intensive housing systems where the laying hens are still mainly kept in cages under controlled conditions. Technical infrastructure and hygiene quality do not guarantee a production atmosphere completely free from pollutants, including potential pathological risk factors. Laying hens and farm workers are exposed to large quantities of bioaerosols in henhouses. Bioaerosols represent a mixture of different biological particles which can, under certain circumstances, cause health and welfare problems in animals. The most important components are dust, microorganisms, and microbial constituents, such as endotoxins. Because of this complexity, numerous measurements and the application of different methods is necessary in order to assess the health effects of bioaerosols and define future research goals. Therefore, a literature review was carried out on bioaerosol composition and the amounts found in laying hen houses. This paper deals with dust and endotoxins: their sources, concentrations, and methods of determination. The wide range of particle concentrations is strongly influenced by the use of different sampling and evaluation methods-and different application and handling of the same method-as well as sampling time, season, and the type of laying henhouse. This paper recommends establishing occupational health limits on bioaerosols for animals and animal caretakers in laying hen dwellings.