I would ask the farmer specifically if there is a place that you can shoot prone. Some farmers will oblige, and put the old toppies in the shade on a chair, and move the young guns to spots where they can lie flat in the sun.

Invariably you are facing one way, and bokkies come at you from the other side. Then you lie dead still, wait for them to almost trample you, they skrik when they smell you, and run off and stop at about 200m and look back, and thats when you move just the trigger finger