We have two sibling Yorkie sisters and have had them for over six months now. They love to play with each other. Although there are times it sounds like a pack of wolves tearing into lunch, they have never brought blood. When they get too rough, they let each other know. Having the two also made the transition from "Momma" a lot easier. They never whined when we put them in their crate at night and actually slept through the night.
The only frustrations that we have had and are still experiencing is the "potty training"! You get two "suprises" and two wet spots instead of one. We were doing great with potty training, but the nasty winter weather we have had in Tulsa these past two weeks has set us back.
I hope your sisters bring you as much joy and laughter as ours have to us!
