BOULDER, Colo. (CBS4) – A former shelter dog that’s missing a foot is now learning to walk on all fours again. “Brownie” tried on his new custom-made prosthetic paw on Tuesday. He lives with a family of four in Westminster and now he’s on new footing that may take some getting used to. Everybody dotes on the friendly 3-year-old dog. They’re excited about his future because he’s had a difficult past. Brownie came to the Humane Society of Boulder Valley in April from an overcrowded shelter in Kansas. He’s active and playful even though he’s missing his left back foot....