Equine Breeder : How To Tell by Looking If a Mare Is Pregnant If your mare has been exposed to a stallion, she may have been bred. It is very difficult to accurately determine whether a mare is pregnant just by looking at her, which is why it is always a good idea to call a veterinarian and have your mare professionally checked if you suspect she might be. The good news is that most mares do show definite signs of pregnancy when they are close to delivering. Equine Pregnancy According to the Ame