In some places(TX comes to mind) you can sell/give feral hogs to authorized slaughterhouses. Now if I am wrong Texans please go easy on me but that is my understanding. The reason they are tied is bc you can't sell a dead hog. In the heat they will spoil rather quickly. This is me assuming that you are watching American Hoggers.
Some people will also keep hogs to train dogs with. I'll avoid the legal hoops one has to jump rough sometimes to avoid being ticketed for transporting a live feral hog.
With all that being said, the best hog is a dead hog
Edit...Sparky, is it legal to transport and release hogs in OK? I ask out of curiosity. I know it is illegal in MS to even transport a live one without permission from Wildlife and even then it can't be released back into the wild....legally.