Old bird diseases occur more among free-range hens

Over the last two decades old bird ?diseases, such as Coryza, Blackhead and Pasteurelle multocida increasingly reared their ugly heads among ?free-range hens. These diseases barely occurred when laying hens were kept in cages. Addressing the growth in demand for animal friendly housing systems, more and more birds are kept in free-range houses and less of them spend their days in cages. Dr Naomi de Bruijn, poultry veterinarian at GD Animal Health in the Netherlands, analysed reports on the preva