title: Air Quality in Alternative Housing Systems May Have an Impact on Laying Hen Welfare. Part I-Dust.
abstract: The new legislation for laying hens in the European Union put a ban on conventional cages. Production systems must now provide the hens with access to a nest, a perch, and material for dust bathing. These requirements will improve the behavioral aspects of animal welfare. However, when hens are kept with access to litter, it is a concern that polluted air may become an increased threat to health and therefore also a welfare problem. This article reviews the literature regarding the health and welfare effects birds experience when exposed to barn dust. Dust is composed of inorganic and organic compounds, from the birds themselves as well as from feed, litter, and building materials. Dust may be a vector for microorganisms and toxins. In general, studies indicate that housing systems where laying hens have access to litter as aviaries and floor systems consistently have higher concentrations of suspended dust than caged hens with little (furnished cages) or no access to litter (conventional cages). The higher dust levels in aviaries and floor housing are also caused by increased bird activity in the non-cage systems. There are gaps in both the basic and applied knowledge of how birds react to dust and aerosol contaminants, i.e., what levels they find aversive and/or impair health. Nevertheless, high dust levels may compromise the health and welfare of both birds and their caretakers and the poor air quality often found in new poultry housing systems needs to be addressed. It is necessary to develop prophylactic measures and to refine the production systems in order to achieve the full welfare benefits of the cage ban.
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, Oslo 0106, Norway. bruce.david@vetinst.no.
authors.forename: Bruce
authors.initials: B
authors.lastname: David
authors.affiliation: Norwegian University of Life Sciences, P.O. Box 8146 Dep., Oslo 0033, Norway. randi.moe@nmbu.no.
authors.forename: Randi Oppermann
authors.initials: RO
authors.lastname: Moe
authors.affiliation: French Agency for Food, Environmental and Occupational Health Safety (Anses), P.O.Box 53, Ploufragan 22440, France. virginie.MICHEL@anses.fr.
authors.forename: Virginie
authors.initials: V
authors.lastname: Michel
authors.forename: Vonne
authors.initials: V
authors.lastname: Lund
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, Oslo 0106, Norway. cecilie.mejdell@vetinst.no.
authors.forename: Cecilie
authors.initials: C
authors.lastname: Mejdell
keywords: aviaries; behavior; furnished cages; health; laying hens; loose housing