When I got Minnie, she couldn't walk...she was the runt of the litter and her back legs had not developed. She weighed just 1.1 lbs and was the sweetest thing I'd ever seen. She immediately claimed me, and is the love of my life! At 5.6 lbs, and 9 months old, you would never know anything was ever wrong with her! She is a typical energenic Jack Russell!