My cousins bought two miniature colts for their kids a few months ago and pastured them in a small paddock right beside our 'big pasture', where the other horses belonging to the family (three mares) could see and smell and 'know' them (my own horses aren't in the same pasture, so no worries about mine there, lol).
The two miniature colts are now both a year old and still intact. One of them got out of the pasture at my cousins and got into the pasture with the mares several months ago. We caught him twice and took him back (and he's very hard to catch, they are both semi-wild/mostly-wild), and both times he got back into the other pasture within the day. My cousins just left him in the big pasture last time he got in because they know that my great grandmother (who owns the pasture) doesn't really care about the mini's being in the pasture.
A few weeks ago, though, the other yearling miniature colt got into the big pasture with the other horses. My cousin's just let it go, because that mini is literally uncatchable unless he's got a halter and long, long lead on him that you can grab and 'reel him in'. Now, I've noticed, they have taken their pasture that the mini's were in down to give their kids more room to play, therefore leaving the two intact yearling miniature stud colts in the big pasture permanently.
They don't intend to sell, either, because I've asked. They just want some horses out there that their kids can essentially just point to and say ''that's my horse''.
I'm not concerned about my horses, as I have them pastured separately from all the other horses and am in the process of building a couple-acre pasture behind the house just for my horses specifically. With the mini's in the big pasture now, I doubt I could pasture my horses in there even if I wanted to, because my gelding hates them and would probably try to kill them...
My concern is the other three mares... Though they aren't mine and I don't mess with them, I still feel a little concerned because they are owned by cousins/family members who just don't care (never had vaccinations, rarely get their hooves done, never had teeth floated, aren’t fed grain at all, etc… they are basically just ‘catch ever few months, ride until tired, and put up ‘til next time’ horses). No one around is concerned with getting the mini's gelded because they're ''too small to breed the big horses'' (no matter what I say or what examples I give them otherwise).
The three mares I'm concerned over are:
A black and white pinto Racking Horse mare, about 13 years old, give or take a few years.
A chestnut Racking Horse mare, roughly 26-ish years old, semi-retired.
A chestnut Racking Horse/Quarterhorse cross mare, roughly 6 years old, stunted growth due to malnutrition as a youngster (roughly pony-sized).
What are the chances the mare's could be covered and actually become pregnant by the mini yearlings? I know it can happen, but I'm crossing my fingers and hoping it's highly improbable…