Grand jury is so named because traditionally it has greater number of jurors than trial jury, called a petit jury (from the French word petit meaning small).
Although mice tend to come out in the night when most of the occupants of the house are asleep or immobile. This allows them to stealthily infiltrate any of your food bags, crumbs etc. During the day time, mice will normally not come out, but if opportunities exist then they surely can.
Because they are on exceptionally good terms with it, I believe cats have much to teach us about the secrets of natural sleep. Cats commonly sleep between 12 and 16 hours a day -- more than most mammals and up to twice as much as humans. Why do they sleep so much? Well, because they can. Cats are predators with few natural enemies, meaning they live under the auspices of a generous, genetically-endowed sense of physical safety.