I have several and my smallest is 3 pounds and my largest is almost 7 pounds.

I have a six week old pup that is trying so hard to get in the mix of the others.

The little pup is so quick I have to watch her like a hawk. She is seperated from the others, other than her mother visiting her and my smallest Itzi. (Itzi is three and knows how to play with pups.) But Itzi is the queen of the Castle, so to speak even though she is the smallest, she will stand her ground with the others. With the smaller yorkies you will tend to watch them a little closer. In my home we do what we call the yorkie shuffle. We rarely pick up our feet. After they have been scooted on the floor a couple of times they learn to stay in front of you are beside you and or behind you. I too have a couple of collars that I use that have bells sewn on them to use until they learn. I attached a picture of Itzi the smallest. Good luck you will enjoy her.