As bad as that sounds...I used to own a mare that was a killer! Had to be kept alone and never pastured with anyone else because she would and did fight till the death of the other horse. One year she went through my pasture and ran to the neighbors house. The neighbors owned about 30 horses at the time, and she went though that fence as well and took on all 30 horses at once! She was in heat soooo bad, she would back up to the geldings in the pasture and when they didn't do anything she would kick the crap out of them! Some how I safely got her out of the pasture and back home again and had the vet come out to check her and tell me why she was like this. He said she was what they termed a Nymphomaniac mare, which ment she dropped multiple eggs at a time. His solution was to breed her, so I did, (she had excellent blood lines and I did do my research to find a stallion that would match well with her. Oh and the foal took first place in her very first halter class at just a month old! It was a mare and foal class but the judge just looked at the foals.) and once she was settled, she was the sweetest mare you ever saw, and even became friends with the ponies that I had for the kids, after the foal was born she kept her sweet attitude, and was pastured with other horses and was never a problem again. So yeah it might work in this case, but really the person should do her homework and not just breed her to breed her.