Typically we find there is little need to sit very long.
The number of pigs we have seen earlier than 30-60 minutes before dark and same after daylight I think I could count on one hand if it wasn't for accidentally bumping a sow one morning around 10 with a bunch of piglets with her.
If I'm after a pig I won't go any earlier than forced. In the mornings I will go as quietly and early as I can hoping they are out and will stay out.
That said have killed em with everything but a spear and knife and the easy way now is wait for dark and pull out the thermal. And that said... saw a boar the other day around noon cutting across the neighbors oats patch...
Cool rifle. Good shot. Great coyote buzzard feed there with that boar. Now go shoot one you can eat.
rost, What thermal are you using right now?
