Horses must be 3 years old before being bred. You need Breedings available, or be a subscriber. New players will have breedings available.
You can breed your mares with your own stallions, or check the marketplace for horses for stud.
Mares will be pregnant for 11 months (or breeds of the parents do not match. The exceptions for cross breeding are realistic… For example, to create an appendix quarter horse, you can breed a thoroughbred and a quarterhorse.). You can breed any horses together, however you may get a generic type horse such as “Stock” as the breed, if the