I haven't seen this film yet, but I want to. Sweetgrass is a documentary, filmed in the area my family visited, about the tough and age old tradition of driving sheep up into Montana's Absaroka-Beartooth mountains. I remember seeing the sheep take over the entire road during the times I was there, but I didn't/don't know the history.
Here's the description:
An unsentimental elegy to the American West, “Sweetgrass” follows the last modern-day cowboys to lead their flocks of sheep up into Montana’s breathtaking and often dangerous Absaroka-Beartooth mountains for summer pasture. This astonishingly beautiful yet unsparing film reveals a world in which nature and culture, animals and humans, vulnerability and violence are all intimately meshed.