Raising Butcher Hogs in Montana Winter

Raising butcher hogs in summer can be an enjoyable experience, but winter time is a completely different ordeal! Frozen waterers, frozen hoses and not to mention the freezing temperatures at night and snow piling up then melting and freezing again. Winter in itself is a difficult task to overcome, but doing it with pigs can be a very different experience. Can pigs live outside in the cold Montana winters? Or do they need to be housed inside? What types of immunities do they need?