Create a teardrop shaped pen out of livestock panels, anchor it, install a trap door and bait it to build a wild hog trap. Place the trap in an area that has clear signs of feral hog traffic or damage.
Construct the pen with 4-by-4-foot sheep or goat panels. This makes the pen modular and able to be disassembled and moved to another problem location. The pen's design should be rounded, avoiding any corners and coming to a narrow entry point at one end. Hard corners can allow hogs to pile up and potentially fall over the top of the enclosure. The narrow entry makes it easier to drive the hogs out and into a waiting truck.
Drive t-posts into the ground about every 4 feet around the outside of the enclosure for support, and make sure there are no gaps between the bottom of the panels and the ground. Install a spring-loaded trap door at least 32 to 36 inches wide at the opening. The door can be saloon-style or flip down from the top. Install the trip wire from the trap door and run it to the back of the pen.
Bait the trap with shelled corn or fermented corn and grease, but make sure not to get it too close to the trip wire or the hogs may set it off before they reach the trip point in the back of the enclosure. This can cause the door to shut before the hog is inside the trap.