@unpublished{orgprints6266,
           title = {Laying hen husbandry: group size and use of hen-runs},
          author = {Helen Hirt and Philipp H\"ordegen and Esther Zeltner},
            year = {2000},
        keywords = {laying hen, animal husbandry, run management, behaviour, Biogefl?gelhaltung},
             url = {http://orgprints.org/6266/},
        abstract = {With regard to welfare reasons, various label productions limit the number of laying hens allowed per flock. The question arose whether the group size has an influence on the use of laying hen runs.}
}