In 2007, I had major surgery for cancer and no longer had the strength or endurance to keep my 90Lb+ Rott/Australian Shepherd, Cody,(an SPCA-save), active enough to keep him healthy. So I went back to the SPCA in Dallas again with a 'check-list': Female; heavy enough to be able to withstand Cody's 'assaults'; naturally hyper enough to give him a workout. The SPCA has pens out in back that enable the humans to see if the animals will 'fit'. The first two did not mix well at all. However, Chrissie, a 35Lb Border Collie-mix picked up off of the streets of Dallas, absolutely fit the bill. The 1st day at her new home was no problem, as she got familiar with each room of her new home and then proceeded to wear Cody's hind-end off! She had him kneeling as she proceeded to show him how smaller dogs 'fight/play' by nipping his ankles.
Today, two years later, they are still best of friends and continue to work each other over in their own rough-and-tumble play style.
Thanks SPCA for giving me time to recuperate and be able to share my "puppies".