Wild hogs are not native to North America. They are native to Siberia and the Northern countries in Europe, where they do very well in winter. Hogs are unable to cool off on their own. They do not sweat, or pant, or have any way to control body heat, so they have to find a cool place to get through the heat of the day. In winter, they become more active. I had a pet pig that was born wild and he would break the ice to get into the pond and fall asleep laying on the snow. I'm not aware of them ever being too cold.
