Funny Folds

Question
I adopted a rescued neutered male mini-pig from the Humane Society about 2 years ago. I was told at the time he was approximately 1-2 years old at the time but they were uncertain. Additionally, he was in extreme poor health and very anti-social. Once I got him, he continued to grown for about 6 mos after I got him so I think they may have been correct about his age. He got to about 125lbs, and his health and social behavior greatly improved to he became a very happy and sweet pig. However, recently his weight appears to be "thinning" and he has a lot more noticeable folding of the skin on all parts of his body including his legs and underbelly. These areas were always fairly full. He is receiving his regular amount of food and is eating normally. He recently received Imovectin for worms and mites.  Is this change in his appearance normal as he ages or should I be concerned that he has a health problem? He doesn't appear to have any other health issues.

Answer
Is he changing in weight or just changing in appearance?
If he is maintaining the same weight or gaining a little, then he's fine.
Pigs grow slowly from age 2 to 4 or 5, when they reach their final, full size. During the last growth phase pigs can change appearance. Their coloration may change, the head may grow (the ears appear smaller), or they may develop body wrinkles. Some pigs will continue to develop deep wrinkles and folds along their backs as well.
If the folds are from gaining a considerable amount of weight, then he just needs a little less food and a bit more exercise.
If the folds are from a weight loss, it's time for concern. Start by checking his mouth, making sure that his teeth are Ok. At age 4 his lower tusks should be protruding from his mouth (unless they were trimmed). Tusks can be impacted, or grow the wrong way into jaws or cheeks, or "lock" themselves together in a way that prevents the pig from opening his mouth or chewing his food.
If all looks good inside his mouth, the next step is to increase his rations or change his diet. If weight loss still continues, it's time for a full veterinary examination.
As long as his weight is stable, he's fine.