Def closed Sunday, my one day off. It looks to be a full day office. Barring a catastrophe they will be open Sat and Mon. If you know which hub your mail comes from and feel up for driving you might be able to get them a day earlier, or even Sunday. Nobody wants bees hanging around on a dock...
You would almost need a separate building well insulated and possibly heated? Trying to keep it below freezing but above 0° ? Or maybe a straw bale building?