Hanging them is to make the meat less tough on the older beasts. As most livestock is killed young these days, hanging isn't really needed. With game though, where its hard to guess the age, my butcher told me to hang them for up to 2 weeks with the jacket on, so long as its not above 7 degrees. So in the winter my garage has been fine. If I shot one now though, I'd hang it over night and butcher it the next day.