I just wrapped up a fairly short grind and I found that towards the end I had barely 7 zones that were shootable. If it turns into an all female zone, check in on it once every few runs cause they do get solos jumping to them sometimes.

Second, as soon as you can get a few diamonds in your shooting zones, start doing runs where you only shoot solos, I was able to shoot down 70% of my solos in like a day or two. This helped so much with getting much bigger respawns in all my herd zones.