Could a shetland pony breed with a 15 hh horse?

No, a Shetland pony cannot breed with a 15 hh horse because they are different breeds with significant size and anatomical differences. While it's theoretically possible for a stallion of one breed to mate with a mare of another, the size disparity could pose serious health risks for the mare and any potential offspring. Additionally, successful breeding typically requires more compatible sizes and breeds to ensure safe gestation and delivery.