Keeping a herd of mares has more to do with the tranquility of the herd than future babies. Jazz gets along with everyone nicely, but somehow he still stirs things up. And I find the mares easier to train/handle. They seem to retain what's been taught if I can't get to them for a week, whereas Jazz needs a reteaching of manners and a reworking of his herd bound issues... Things are very quiet in the pastures, but all mares is uneventful for the most part. They aren't as rough.
I think mare stare will be back in chit-chat--that post was another horse they were watching... but I could be wrong.