Just an observation.
When Hogs change there eating times it is normally due to hunting or other types of pressure. lack of food will also make them extend their feeding time in to early morning and early evening. If they find no pressure, they will adapt to their new schedule.
I am sure there are other reasons but this is what I have observed over the years. After long absences from out hunting lease, we often see them in the middle of the day for a few days and then with the pressure, they return to feeding at night.
We try not to educate them and kill everyone we see (If we can ) but some witness the carnage and decide that night is safest. Inter the night vision hunting.
I don't know how smart they are on a scale of 1 to 10, but they do learn fast and seem to adapt to our schedule better than we adapt to theirs. So as they say "Adapt and overcome"
J E CUSTOM