One of the hunting clubs I am in has a high hog population. We have feeders out year round on timers that go off after dawn and at about 3pm... this way they get used to the feed showing up during the daylight hours. Some say hogs are nocturnal, especially in the summer months. I get them on game camera at all times of the day even when its in the triple digit temps.
The land owner is setting large pens or single cages ?
The best way Ive found to eliminate high #'s of them is by pens with swing gates or trap doors. Ive seen as many as 30 in a catch pen after one night.