the good lines are kept tight within a group of terrier men whos same attitudes and standards are much the same, it prevents them from falling into the hands of idiots to manipulate and say this is blah blah bred,and it has papers to, gis your wallet and il give you change , they are kept close for future improvements to the line, thats why good lines are still going to this day, and when a litter is needed, its to rejuvenate stock, then and only then is there a mating !!! and they are kept within that inner circle