My little girl, Katie, has some Durrer in her pedigree. A lot of my breeder's dogs have Durrer. Katie has Durrer Preferred Stock also in her pedigree, but it's generations back. Katie was with her breeder until the age of three. Below are photos of Katie and her pedigree.
CH Rigair Yabba Dabba Doo (Kate)
Kate's pedigree.
RIGAIR YABBA DABBA DOO - База Родословных Йоркширских Терьеров - World Pedigree DataBase Yorkshire Terrier