Puppies of Yorkshire Terriers begin to change color at 4 months. If the dog was born with a silver-blue coat, some members of the breed become noticeably lighter around 6 months and take on a white hue. Towards the end of the year, they develop a hue that is particularly unappealing to breeders since it shows the Yorkie's filthiness and is steel-whitish with a silver tinge.