Health of Commercial Egg Laying Chickens in Different Housing Systems.

To determine which type of egg-laying hen housing was best for the chickens, the workers in those housing systems, the environment, and society based on food safety and affordability, a combined research project involving egg suppliers, food manufacturers, food service representatives, and food retailers, as well as research institutions and nongovernmental organizations, was performed. This study reports the hen health and welfare portion based upon veterinary health inspections and compared mortality rates, skeletal abnormalities, causes of death determined by necropsy, and titers to infectious bronchitis and Newcastle disease viruses. Birds were housed on a preexisting Midwest layer complex, which consisted of conventional cages (CC). New houses were built adjacent to the CC house where enriched colony cages (EC) and an aviary system (AV) were installed. Two flock cycles from housing to 78 wk of age were followed. Total mortality was greatest for AV, while CC and EC birds were similar. Keel bone fractures were greatest for AV, next greatest for EC, and least for CC birds. Other skeletal abnormalities were greatest for AV birds. Birds dying from being caught in the structure, pick out, and persecution was most frequent for AV and next most frequent for EC, but nonexistent with CC birds. Infectious pododermatitis (bumblefoot) was most frequent for AV, next most frequent for EC, and essentially nonexistent for CC birds. There was little to no effect on antibody titers based upon housing type. Based upon these findings, it appears that EC housing is better for the health and welfare of egg-laying chickens than CC or AV housing.