Miniature horses are a bit of a challenge to breed.
The gestation time is approximately 11 months, or 340 days. It is best to be in attendance at the foalings because the mare may have a problem and you can frequently help them and save the foal, mare, or both. This gives the foal immunity also. You need to have all the preparations made and ready to go about 2 weeks before the birth is expected, you never know when it might happen early. Have a clean stall prepared with clean, dry straw bedding.