Bighorn sheep spend most of the year in two separate societies that barely interact. Rams band together in bachelor groups, ewes form nursery groups with lambs and yearlings, and the two only come together for the rut. What you are looking at is the half of the population that does the actual work of keeping the species going.

The ewes choose where to raise lambs on one criterion above all others: escape terrain. Steep, broken rock that a predator cannot move through quickly is worth more to them than good grazing, so nursery groups will accept thinner feed in return for being able to get onto ground where a coyote or a lion cannot follow. Lambs are climbing within days.

It is also why bighorn populations fragment so easily. They will not cross open flat country to reach another mountain range, because open ground is exactly what their entire survival strategy is built to avoid. Separate a herd by a valley with a road in it and you have separated it permanently.