The Poodle is a formal dog breed that comes in three varieties:  Standard Poodle, Miniature Poodle, and Toy Poodle. The hair under the tail should always be kept short to keep feces from matting in the dog's curls. Most owners also keep the feet and face clipped short to prevent dirt from matting between toes, tear stains on lighter-coated poodles and food from matting around the dog's muzzle. The most common serious health issues of Standard Poodles listed in order of the number of reported cases in the Poodle Health Registry (20 August 2007) are Addison's disease, gastric dilatation volvulus, thyroid issues (hyperthyroid and hypothyroid), tracheal collapse, epilepsy, sebaceous adenitis, juvenile renal disease, hip dysplasia, and cancer. Standard Poodles are also susceptible to some health issues usually too minor to report to the health registry.