I have had several stallions. Personally, I always work to socialize them into some sort of a herd.
It may take time, but I find that they are happier, healthier, and tend to work better when they aren't constantly thinking about BREEDING mares...if they are living with them, they tend to lose the focus on the mares as being ONLY for breeding.
Now, this is MY experience, and MY opinion, but it's what I do. If I raise a colt as a stallion prospect, he is raised in a mixed herd. It can be difficult to make sure he's always in with bred mares, so there are no "accidents", but this is what works for me.
When I have acquired an older stallion, whether he be right off the track, or a horse that has been breeding, they get acclimated into a social environment at their own pace. Some take to it faster than others. ;)
I have VERY good, old mares that know how to "teach" a horse his manners without being overly nasty (for the most part). I have had ONE stallion just "not get it" right away and he ended up with a pretty big hematoma on his chest. He didn't get the signals for a few days, and this was a horse that had been bred in hand for YEARS. He figured it out, and was none the worse for wear.
Proud Breeder of Trakehners and Anglo-Trakehners