Having four teats is not a problem most will not be big enough to provide milk but the odd ewe can milk and be suckled on all four teats . Was the article about the WHELDON ( not sure of the spelling ) sheep which were selected on having 4 functioning quarters , ive tried to find information unsuccessfully in the past , before the war a german scientist was also breeding for the same trait but i assume they were eaten , a couple of breeders now are looking into selection i belive . You need to select rams with 4 teats