Alternative breeding strategy in which two adult females and one adult male are co-housed resulting in two litters. One of the adult females must be removed prior to parturition such that only one litter is born in the cage unless breeding records demonstrating problem breeding are submitted as scientific justification for overcrowding and approved by the IACUC. Singly housed pregnant females or stud males should be labeled with a blue tab as described in the Identifying Single Housed Animals SOP.