I decided to drop by and read the new posts before I pass out ><
Thank you to everyone who gave me the stallion's names who have smaller herds

Inbreeding and line breeding is common is breeds were the risk is worth the possible reward. See mostly in Thoroughbreds, but also in many other common breeds, it is used a tool to either locate bad genes and remove them, or to reinforce the inheritance of good traits. The possibilities of good traits within the common breeds is seen as outweighing the risks because of the amount of horses in the breed, and the competitive need to have the best foals. Alternatively, inbreeding is used to make already tiny breeds smaller. Outside of these breeds, it isn't see as commonly. The horses can be perfectly fine, or they can come with a mess of issues. Generally, the foals have a tendency to be smaller in height and weaker. We actually had an accident within our little herd. Our gelding (He was a stud for about five years) Starkey bred his mother. Turns out the vet had messed up when gelding him...fun ><
Their foal seemed fine. Then, when she was only two, her stomach turned over one day. This killed her. She had no other health issues, other than being slightly more fragile than our other horses. We do not know for sure what happen, or the cause, but no other horses were affected.
Inbreeding can happen in the wild, although the horses are generally observed 'preventing' it. Along with the mares and stallions leaving when they come to age, other things get in their way. Mothers will thwart any advances from males, the lead will refuse her, and a couple other things I can't remember. Outside of the herd, if the ages are far enough apart, nothing can truly prevent siblings from mating. Although, the age difference would probably have to be a couple years for them to not recognize one another at all. If it does happen, it likely won't be a common occurrence

I've been reading up on this stuff since joining, and for a HARP group I'm in, so I figured I might as well be a butt and talk about it. (Plus I get to mention one of my lil babies ^^)
Have a nice night folks!