I asked that stupid question because i am sure you do not want to use chicken mesh but probably you meant link mesh (There is a difference between the two) .Polyposts are certainly a bit expensive and therefore good old red cedar would suffice.If you were to consider costs,link mesh of height 6' X 54' length goes for kindu 3.6K while a roll of barbed wire (610 metres equivalent to 1830 feet) goes for 4.2K while it's 480 Metres counterpart goes for kindu 3K.Definately there are savings in barbed wire and as Gathige says,the trick is on concentrating the stretches on the lower 4 feet and thinning as you go up.You will still end up with a decent and robust fence.

@webish yes there is 10 acre i hear going for 1.5 mio its along the road if interested tell me i give you the number of my good masai friends.

I was in the same predicament sometimes back -Kisaju area. I fenced using barbed wire with normal cedar posts. Planted bougainvillea perimeter fence with some tress. Instead of employing somebody, construct a simple temporary site house. Give or rent cheaply.

@QD, Also mark/paint the posts at half-length with a permanent paint ( ile rangi ya mafuta). That way in case they are uprooted and stolen you can easily identify them. Red is good colour as it is conspicuous.

Hawa watu wameona mengi. Good advise.