Charles River Laboratories International, Inc., an early-stage contract research company, provides drug discovery, non-clinical development, and safety testing services. It operates through three segments: Research Models and Services (RMS), Discovery and Safety Assessment (DSA), and Manufacturing Support (Manufacturing). The RMS segment produces and sells research model strains primarily purpose-bred rats and mice for use by researchers. It also provides a range of services to assist its clients in supporting the use of research models in research and screening non-clinical drug candidates, including genetically engineered models and services, insourcing solutions, and research animal diagnostic services. The DSA segment offers early and in vivo discovery services for the identification of a druggable target through delivery of non-clinical drug and therapeutic candidates ready for safety assessment; and safety assessment services, such as bioanalysis, drug metabolism, pharmacokinetics, safety pharmacology, toxicology, and pathology services. The Manufacturing segment provides in vitro methods for conventional and rapid quality control testing of sterile and non-sterile biopharmaceuticals, and consumer products. It also offers specialized testing of biologics that are outsourced by pharmaceutical and biotechnology companies; and avian vaccine services that provide specific-pathogen-free fertile chicken eggs, SPF chickens, and diagnostic products used to manufacture vaccines.