ABSTRACT: Erysipelothrix rhusiopathiae septicemia was diagnosed in three cage free commercial layer flocks from Washington State that experienced increase in mortality and slight drop in egg production. E. rhusiopathiae was isolated from multiple organs and from environmental samples. An agar gel diffusion test of several E. rhusiopathiae isolates confirmed presence of serotype 1b and multiplex real-time PCR of the surface protective antigen (Spa) gene confirmed presence of SpaA. Bacitracin administered via the water reduced mortality minimally and only for a short period of time. Mortality was finally controlled by vaccination with a live attenuated swine E. rhusiopathiae vaccine delivered via the drinking water. This is the first report describing the use of an attenuated vaccine to control an E. rhusiopathiae outbreak in a chicken flock.