Hog killing time is after the first frost, so the meat won't spoil during the butchering. I haven't been to one since I was a kid but some of my folks in Kentucky still butcher their own hogs and cure their own hams.
I can remember "Butchering Weekends" with my Grandfather and his brothers: everyone pitched in to do what needed to be done to prepare the larder for winter. One year Uncle Dave added so dang much sage that it made the sausage inedible...but what great times they were, back when.