I also have 4 small breed dogs around 10lbs. We brought our GSD home he was 8 weeks old he was around 8lbs. I have had no issues that get along great. I do worry when they play Tax (GS) will be to rough as now he is 30lbs. I just watch them closely, I think he realizes they are small. When they don't want to play they let him know.I usually let them work it out unless things get to rough. My advice would be to always keep an eye on them when they are together. Hope this helps.