
There is only one Yorkshire Terrier breed. No toy or minature, just Yorkshire Terrier. Any breeder that tells you different does not know enough to be breeding, and be in a position to offer you the after sales care and advice you are entitled too.
I suggest you contact the KC 0870 606 6750 for details of a Yorkshire Terrier Breed Club. Being a popular breed they are likely to have Regional and National Clubs.
The secretarry will be able to advise you of anyone expecting or having puppies available. If she knows of no-one and you plan to try newsapaper adverts I would ask him/her to tell you of any known puppy farmers in your area, so that you can stay well clear of them.