A multiple-age egg production farm was conceived, designed, constructed, and managed with the goal of blocking the introduction of preventable poultry diseases and infestations. Fifteen years after conception and 13 years after housing the first hens, the 4 million-hen farm remains free of Mycoplasma gallisepticum, infectious laryngotracheitis, and Ornithonyssus sylviarum. Annual savings in vaccine use exceed the estimated annual costs of the biosecurity program. The cumulative design, construction, and operation of this farm are a successful demonstration of practical, effective biosecurity on a commercial poultry farm.