I have a question about horses in the wild?

I've heard that with Zebras young females generally get a little restless when they're breeding age, and outcast young males pick them up and form their own herd. I'd ume with wild horses it's something similar. Of course, with Zebras, several family groups coexist to form one megaherd, so a young mare doesn't exactly have to go far to find a stallion that isn't her father.