Why not spend a day with the pig farmer and go through the motions with him? I think this would help you get a perspective on what the lifestyle of a pig farmer is like and at the same time you'd get to scope out the lighting situation at all points during the day and the layout of the farm. One of the hardest parts of this assignment sounds like there's so many things you can do that you might not even know where to start thinking about it. Maybe a day with the farmer can open up a dialogue of thought that would allow you to view your assignment in a new light.