[mscat]

I did have to rehome a yorkie who was about 4 yrs old. She was always fighting aggressively with my other 2. After rehoming her the new owner text me after a couple of weeks having her. She told me that the yorkie had bittened her 4 yr old on the nose. The child always was loving on her and the dog snapped. The child was ok, he did not need stitches or anything too serious. Because this was a rescue we did not have the background information on her. The new owner took her to the vet, and did find out she had a health issue.
It is a good idea to take your puppy to the vet and make sure he is completely healthy. I am glad your going to teach the children not to play so rough or tease him anymore. At 6 months old your yorkie is still getting all his adult teeth and was taken away at too young of age. That is important because the pup has not learned propper social skills. So it is up to the owner to teach him. He is only a puppy so their is time for him to learn and to be trained. I would always have the children sit down calmly and pet him nicely. Playing fetch is ok, just not any games that promote aggressive play.
Every toy breed of dog has the ability not to like small kids very much. Because of their small size , they can easily feel threatend.