Diseases in chicks and laying hens during the first 12 years after battery cages were banned in Switzerland

Between 1992 and 2003, a period of 12 years after the definitive ban on battery cages in Switzerland, more than 10,000 replacement chicks and laying hens were examined postmortem. There was a significant decrease in the incidence of viral diseases, mostly due to a reduction in Marek's disease, but there was a marked increase in bacterial diseases, particularly since 1999, mainly due to colisepticaemia in young laying hens. There was a steady...