I have bred Stan to bitches that the whole litter did not turn out though... these were to gyps that were slow starters themselves (3 to 4 years before working well), and I culled the entire litter. Had I waited past 2 years of age, the dogs may have turned on, but 2 years with an unknown background breeding is where I draw the line.

Had I bred the gyp to a proven dog that had a documented lineage, I may have waited past the 2 year marker.