We tried adding a sister for Sophie but it didn't work out well and I had to let my niece adopt her. Hazel became very aggressive with Sophie over everything from the couch to toys. After trying for some time to work it out we decided since we had Sophie first and didn't want her bullied we would let Hazel go with my niece where she could be the only dog. Sophie fills our lives with so much joy that we decided to be a one yorkie household.