Horses do NOT have ponies. Ponies are an entirely different category, which is based on size. Horses have foals, which are categorized as colts, or male foals, and fillies, or female ones. A pony is classified as small, medium or large, depending on the height. A horse MAY produce a pony if there young only grow to pony size. Your horse has to reach 2 and a half years old to be sexually mature. The same thing in truth. It MIGHT be a pony if the male is also a pony. You can test it on horse that if you have a connemara, and you choose a male mustang, you have a 60% chance getting a connemara and 40% chance getting a mustang.
a horse can only have a pony foal if it was bred to a small or medium pony other wise it is a big large a normal horse or a big horse