I had a 9 yr old and 6 yr old Bichons when we first brought Madison home. They haaaated eachother for a few weeks, until one day we found that Madison had brought some "spunk" into the 9 yr old and they were playing around together! Ever since then they have been best buddies (only a growl every once in a while)...I think it just takes some time and some extra lovin for the older doggies