Welcome to YT and kudos on doing research before getting a yorkie.
As to your question about a yorkie with a 4 year old; I would say it all depends on the 4 year old. I would never let them be together without supervision but feel silly saying that as I (and I am sure you) would not leave a 4 year old without supervision anyway. I have seen 4 year olds that would have no problem being gentle enough and having respect for a tiny puppy. I have also seen some that no matter how much supervision, would probably wind up harming their puppy in no time.
I have a 2 year old grandson that I let pet and even hold on his lap the puppies from my last litter and now the one I have kept who is 5 months old. I did not want to institute a "no touch" policy because I think it is important that he learn to be around tiny animals. He knows that any time he wants to hold them he can sit down on the floor and I will bring a puppy to him. He has been very gentle and loves to pet them. I would not leave them ever in a room together without me being right there in arm's reach, but as long as he has that close supervision, he seems to do just fine.
So, it is a judgement call, you as the mother have to make. You know your own child better than anyone. You may find many breeders that just have a hard and fast rule not to sell to families with small children. Offer to have them meet you and your daughter and see how behaved she can be around puppies. It might make a difference to some. Try not to take it personal if they do not agree to sell to you. Many have had experiences that make it impossible for them to chance it again. But I am sure there will be some that will give you a chance, if you have decided your daughter is mature and gentle enough.
Again, -- WELCOME!
