should be perfectly tractable and free from any vice and not subject to fits or other similar ailments. A mouse with absence of whiskers, blind in one or both eyes, carrying external parasites, having a tumor, sore or legs with fur missing, suffering from any obvious disease or deformity or kinked tail shall be disqualified." Pet care Caging A cage with wire bars and plastic flooring is the most common type of housing. A span between cage bars of less than prevents young mice from attempting to escape by forcing themselves through the bars, where they may get stuck. This can also help prevent predatory pets such as cats, dogs, arthropods, snakes, and other carnivores from killing and eating the mice. Mice are naturally cautious of rats, who may kill and consume them. This behaviour is known as muricide (cf. Muricidal test). The mouse cage should be cleaned every week to prevent odour and disinfected only if a mouse has been unwell to prevent infection and disease. In the wild, mice are able to co-exist with other small rodent species. Compared with larger mammals, the mouse's small body makes it difficult to regulate body temperature effectively. Thus, drafts and large fluctuations in temperature can adversely affect the health of mice. The best products for use in cage bedding are aspen wood shavings. Paper-pulp-based products are also available, as well as a variety of recycled products, though newspaper products may contain inks, dyes and other chemicals from the paper making process. Cedar and pine, even kiln-dried, should not be used as they release aromatic oils that damage the respiratory system and can cause or exacerbate chronic respiratory disease. Recent research suggests that paper-pulp bedding may allow very high concentrations of ammonia to build up in cages, especially those with little ventilation. Small hideaways and toys (such as a cardboard tube) are good to have in the cage. Commercial toys are also available. Mice love to run on a wheel, which provides stimulation as well as exercise. In the U.K., most show breeders keep their mice in wooden boxes measuring about by by , although there has been increasing use of plastic storage boxes. Feeding Food for fancy mice can range from specially formulated feed mix to kitchen scraps. Carrot, spinach, lettuce and other vegetables are often enjoyed by mice but should be given sparingly as such foods can result in diarrhoea