Currently our valley is the home for 12 horses.  They are fat, happy and have lush green pastures.  I've often wondered, if we had a wild mustang herd here in Wisconsin, how many acres would a herd of 12 need to survive?  It think that our one little valley would be enough during the summer, but the winter would be the deciding factor.  I'm not sure horses could make it in WI in winter no matter how much land they had available to forage...there is usually just too much snow.  But it's interesting to ponder.  These horses are 4 mustangs (3 at this very moment since Griffin is away at training), 1 quarter horse, and 7 Tennessee walkers.