Accurate characterization of the foxhound is essential to development and definition of quality control programs for this laboratory animal. Blood pressure, growth rate, physiological and behavioral adaptation to environmental stress, birth weight and prediction of neonatal survivability are among the areas studied. Outdoor paddock housing constitutes one major environmental variable. Uniformity among animals, within and between studies, significantly enhances validity of research results and reduces costs by eliminating unsuitable animals and decreasing the need for repetition of studies.