As a "Texican" and adopted "Okie" with "some" hog experience.
In my experience, when you shoot up a "sounder" (a group/herd) of hogs, they either go nocturnal OR leave that area.
Nature hates a vacuum, another sounder will replace them, but it may not be overnight!
When we trapped hogs in southern OK, we had to move the trap when we caught hogs.
Feral hogs ain't stupid and the will get trap wise.

You're not doing anything wrong. Take a break for a week or so. More will eventually show up.