You never know. I bought a mini stallion four years ago. They saw him get out and breed one mare, resulting in a filly. Last year she contacts me concerning a couple of colts born that same year. None of her other stallion (on property at the time of breeding) DNA matched with the two colts. When she checked the DNA with my stallion and the two colts, it confirmed he was the sire. She has really good fencing and never saw any hanky panky between my stallion and the other two mares. To this day she has no idea how he did it.