Chickens and rats have an important part to play in Charles River Laboratories International's specialty portfolio of medical products. The company produces lab rats and mice bred specifically for use in medical testing through its Research Models and Services (RMS) segment. It also provides contract drug discovery and development services, including toxicology and pathology, through its RMS, Discovery and Safety Assessment, and Manufacturing Support segments. To a smaller degree, the company also supplies pathogen-free, fertilized chicken eggs used in vaccine production. Charles River Laboratories, which traces its roots back to 1947, has operations in 17 countries around the world.