In Europe, especially in a cold climate of Scandinavian countries, it was tradition to age most game meat for several days to a couple weeks. Usually game animals were hung by the neck, and cleaned when they were deemed "seasoned". In some cases this was determined by when the body fell from the neck. Leaving the skin, fur, and feathers on prevented excessive drying.
Edit: It is difficult to find English language sources for pre-industrial meat and game processing, because this is dependent on the temperature, time, humidity, age of the animal, condition of the carcass, etc. Basically, it cannot be standardized for teaching or publishing.
https://www.lovefood.com/news/59000/guide-to-game-rabbit-and-hare
https://honest-food.net/on-hanging-pheasants-2/