Welcome to Pet Talk Kathy, Pepsi and Luke...As Logan says, I wish it were under happier circumstances. It's expected that our seniors will slow down as they enter there golden years. Many dogs at age 12 have great difficulty doing stairs, no longer have the energy for long walks, etc. A thorough physical exam should help to rule out a host of physical causes for her lethargy and mobility problems. I request a routine blood chemistry and complete blood count yearly once my kids reach senior status. Amazing that she doesn't suffer from arthirits though I'm sure the muscle atrophy in her one leg is keeping her from being as acitve as she once was and may be causing her pain. I would discuss with your vet all the options available, such as dietary supplements, glucosamine/chondrotin, pain medications etc. I have a dear, dear, senior Beagle friend named Gus, who at age 15 is still active and enjoying life. A daily buffered aspirin helps greatly in easing his aches and pains. Perhaps you could discuss that option as well. I'm sure the loss of Tiffany has also greatly affected Pepsi emotionally Hopefully with a bit more time, Luke will help to lift her spirits. It's hard getting older Please check back with us and let us know how she's doing. You're a dear soul for giving these deserving seniors such a wonderful, caring, loving home Hugs to you Pepsi and Luke! Sandra