states. but those roundups have been met with backlash. kati weis of cbs station kcnc in denver has tonight's journal. >> you want clean water. >> reporter: at a prison ranch in southern colorado, inmate david jackson and alex cockrell spend their days caring for these once wild horses. the mustangs path to this pasture is not without controversy. a few months ago these horses lived free on public land in colorado but the state's wild horse specialist steve leonard say there are too many horses for the land to support. >> we still have this lack of forage for our wintering areas i don't believe the horses would survive the winter. >> this fall, the bureau of land management rounded up more than 700 forces in the state for relocation. critics of the roundup push for birth control instead of that relocation. >> it's never easy to see entire families, i mean really generations of horses that are no longer going to be on the