Not called Billy Fred's anymore, now called River Fields. Also good luck to you to find hog hunting. Most all private land, very little if any public hunting land. What there is, it's heavily controlled by the state. Make sure you know where the boundaries are located, land owners in Texas are very protective of their lands and the trespass laws test to that. If I'm not mistaken you'll also need to purchase an out of state hunting license, even for taking predators. River Field's should be able to clarify that as well.
I am a land owner and I am glad the trespass laws are here, just wish we had some more public land to hunt on. I had hogs on my property southwest of Amarillo, but Parks and Wildlife came in with a helicopter when first spotted and eradicated them along with some local farmers helping out. Hogs are just too destructive to allow footholds and the agriculture here doesn't need another pest. Specially one that prolific and that destructive.