That looks like the competition area at the National Fieldays in the Waikato last month. Bear in mind that in a practical situation you'd have time and machinery to level off ground rather than use so many posts over a small hill area. These guys are fencing fast and with enormous attention to detail for the judges. Normal post spacing is five posts to the chain (22 yards) and then five battens between each post. Around here we rarely use more than seven wires, although a couple of weeks ago put in an eight-wire boundary fence - I'll get a picture uploaded when I can. The battens don't do much to the construction of the fence, but create a stronger structure so that animals are less able to push their heads through the wires. Often we'll put an electric outrigger or two on the fence to stop such pushing - don't like using barbed wire, which would be the former method of discouragement.
We might have a lot of timber trees growing here, but presently most of them seem to be going for export and getting hold of fence posts is like looking for the proverbial hen's tooth!
