Gosh, what an unfortunate situation! Far too hard to tell in type who is at fault, besides it doesn't really matter anyway. Your horse has already been moved and she is either pregnant, or she is not and all you are left with is damage control. What's most important right now is that you get your mare checked out by a vet and begin assessing your options if need be.
Legally, it wouldn't be worth your time and effort trying to sue to recover your vet bills because it will be virtually impossible to prove who was at fault, it is a case of 'he said, she said' at the end of the day as to whether fencing/boarding situation was appropriate and the other owner may even claim that you intentionally bred your mare. I am not suggesting you did by any means but how would you prove otherwise if they claimed that?
Also, I am not even sure if you can demand a paternity test for horses, would the owner of the stallion have to consent to a DNA test? More 'he said, she said' if you can't prove paternity, ugh what a nightmare.
I hope for your sake that your girl isn't pregnant.
All horses deserve, at least once in their lives, to be loved by a little girl.
Last edited by sarahver; 05-25-2011 at 12:11 AM.