Yes, yorkies are known for having trouble losing their baby teeth on their own. I would definitely wait until 8 months of age to have your pup spayed/neutered if it hasn't already been done. This way, while under anesthesia once, the teeth that need to be removed can be done at the same time.
They will definitely need to be removed, though. If not, it can lead to fast gum disease as the food can get stuck in between the rows. Make sure you brush your pup's teeth well until they are removed.
ETA: Just saw the post above mine. Why are you wanting to mate him? Curious.
__________________ Terri, proud mom to Mandie  & Shelby-Dale  |