Every ranch is different. But on federal permits, you may own 20% of the land acres within an allotment that produces 50% of the feed. The reason those acres are private is because someone homesteaded them. However, there are several parcels of private land and they generally are on the creeks, springs and meadows that at some point in history (late 1800s to early 1900s) supported a homestead. That is why the private land may contribute more forage on a per acre basis than the federal land. It isn't cost effective to fence the private parcels and if a lot of the water sources are on private, it just needs to be managed in common with the federal land. If whatever use limits the feds set are met, then have to move off the pasture even though you might to use the private land more. If the allotment allowable utilization is met cows have to be moved off federal ground. They then go home, to a different allotment, to a private lease or whatever the ranch has available. In the western valleys, the home ranch land usually irrigates and puts up hay. When cows come home they go out on meadows that were hayed or maybe federal allotments close to home, or whatever is available to sustain the herd through calving and do it all again. Some outfits have to truck to their summer ranges, which may be 30 or 100 miles away from the home place. Other ranches are lucky enough to open a gate and be on their summer ranges. Some of the big sheep outfits are based out of Northwest Colorado or southwest Wyoming and will winter sheep on the desert and lamb there, then trail 100+ miles across several BLM allotments to Forest Service allotments in the mountains to summer, then wean in the fall and trail back to the desert. Many of the old sheep outfits have converted to cattle, so they hold AUM rights across all the allotments they used to trail across, but managing cattle doesn't work the same way, so there will be exchanges of use with other permitted to try and balance it out. The history of the ranches that are heavily dependent on federal land is pretty interesting in some cases.