Not as a breed of dog, they don't. I remember seeing a three legged dog some years ago. It had had a leg amputated, and had no trouble moving about on three legs. So, three legged dogs exist only in the capacity of an amputee.
Charlie the Three Legged Dog - 2011 was released on: USA: 11 June 2011 (Delray Beach Film Festival)
The three-legged dog is named Cody.
Edward Steichen.
A three-legged dog named "Trowser".
I came to get the man who shot my paw!
You should probably take your dog to a veterinarian, particularly if your dog became three-legged through an amputation to control cancer or infection - the cancer or infection may have spread to the back leg she now can't walk on.
Dog Tales - 2007 Adopting Three Legged Dogs Pug Profile 1-7 was released on: USA: 15 October 2007
Youtube is your best bet.
Practicing the three-legged dog yoga pose in your daily routine can help improve balance, strengthen your core and upper body muscles, increase flexibility in your hips and hamstrings, and promote a sense of calm and focus.
Three legged stands are often called stools. In photography a three legged stand is called a tripod.
this is quite common in small dogs, eg jack russell. it is called patella luxation which is where the kneecaps dislocate causing a three legged hop for a step or two. there is nothing to worry about, but you can get it corrected with surgery.
Not naturally. Dogs can be born without legs or lose them through an accident. There is a video on You Tube of a dog that only has it's hind legs and it walks upright.