The splitting gene can cause uneven results with three or five horns being found occasionally. This same gene also sometimes causes the top eyelid to divide, creating a “split eyelid”. Breed enthusiasts regard this as a defect and animals presenting split eye lid seem to have a greater propensity to develop eye infections. Split eye lid does not occur in two-horned animals.
Some breeders argue that the constant use of four-horned animals will create uneven horn patterns in the offspring. On four-horned stock, horns sometimes break off. Breeding from two horned stock alone will mean that there are no four-horned lambs. Whilst polled ewes, this means ewes without any horns, are identified by the Rare Breeds Survival Trust as being “undesirable”, genetically they are acceptable. This particular characteristic is a feature of four-horned sheep and flocks with only two-horned animals will also not present polled lambs.
Whatever the configuration of horns, they should not grow into the face or impede grazing. Four-horned lambs may also have completely different horn patterns from their parents.