PIGS WITH 3 EARS !

Driving around all day, as i do in my job,you come across some pretty unusual sights,people and signs.One of the funniest signs i've seen was on the side of a farm building advertising what was for sale in the farm shop. The bit that got me thinking was the 'pigs ear's, 3 for a pound'!Don't they normally come in pairs, what happened to the other one? or is there a secret farm somewhere that;s breeding a super pig with 3 ears .