Welcome to YT. Before you mated your female the first time, did you check her genetic back ground several generations back, on her parents, grandparents, great grandparents, etc. to see what and how those litters were, and did you do the same on the stud that you used. If you use other studs their genetic back ground should be research several generations back also. If you did the proper genetic research on both mating pair you would know if pure black puppies run in sire or dam genes.
A pure Yorkie cannot produce a Biewer. Biewers are a breed of their own, your yorkie may be a mix and not a pure yorkie that she is throwing tri color pups blonds, chocolate now pure black. You can do a DNA on both sire and dam to see if you have pure yorkies.
__________________ Joan, mom to Cody  RIP Matese  Schnae  Kajon Kia  forever in my  A House Is Not A Home Without A Dog |