A badly limping potbellied pig?

Question
Our male potbellied pig, Pinky, has been limping badly lately.  It's only on one leg, the left hind one, I think.  We considered arthritis, but he's only around 3 years old, plus is far from overweight and nails trimmed by cement.  We haven't brought it to a vet yet.  Any suggestions?

Answer
Piggy might have injured his leg. Check the whole leg and hip for swelling or sore spots. Pigs can do stairs, but the chance of injury is great, they do much better with ramps. Also, slippery floors can cause injuries, so keep piggy off slippery surfaces or put down mats or rubber-backed rugs so piggy has good traction.
Some people teach their pigs to "Sit Up" or "Stand Up" on the hind legs only. This trick is very hard on the hips, so avoid having him do this particular trick.
Another problem could be jumping. Piglets can leap high into the air almost effortlessly. As they grow older it becomes harder for them to do this, and harder on their bodies, so this is another way he could have injured himself.
Check his foot, make sure the soft part is free of injury and nothing is stuck in between his toes.
Arthritis is often associated with age and obesity because symptoms tend to appear with age and obesity makes the problem much worse. But arthritis can attack at any age, and can affect bone or connective tissue. If arthritis is the problem, a prescription medicine is the most effective long term solution.
Pot-bellied pigs, like all swine, are prone to an assortment of hip problems. A mild infection or minor injury (often so minor the owner is unaware of it) can cause the bone in the hip to deteriorate. So can congenital (birth defect) conditions. This sort of thing can only be diagnosed with an x-ray. Treatment can range from a special diet or supplement to medication to surgery for extreme cases.