Horses in real life have an unlikely chance of carrying twins to full term and usually ends in the death of the second foal. However, this is Second Life and we can enjoy something that we can’t get in the real life. We don’t like the idea of foals dying so we made the rule that they would not die but would have a chance of an extra small horse. The small horse would have the hand height of 11 hands. This is also a great size for our child avatars as a mini horse would be.
It is a rare chance to get twins and it is a rare chance in the chance to get an 11 Hand Mustang.