well this unfortunate I’ve had the same horses three mates one stallion for over ten years and never had a baby. I didn’t even know my stallion had ‘bullets’
So sorry for your loss.
You are lucky you even found the evidence, many don't even know their mares miscarry at this stage as the fetus is so small, it's rarely found.
What a shame. How is the mare doing? How did you happen to find the fetus? The one saving grace is you didn't know she was pregnant, so it's a bit easier to take.