Food for thought- I have several hunting spots that, in the absence of hunting pressure, the herd will stay in the same spot forever and browse the food down to the nubs. This occurs year after year, to the point that they will actually begin browsing on knapweed rather than moving on in search of fresh food. Meanwhile, the next drainage over hasn't been touched by elk in years and has surplus feed. Why? My guess is that the lead cow keeps going back to the same spot that she knows, year after year. Perhaps if you shoot the lead cow out of the group, the group will have to a fresh start as far as home range and will venture in to new areas, giving the old spot a rest and utilizing a new area that hasn't been browsed in years. I'm no biologist, and this is just a wild guess, but it seems like this would be a healthy re-start for the herd every few years.