If you are having a new wooden / post and rail fence put up to contain horses / livestock ensure that a electric fence is added to the wooden fence.
Unfortunately all animals like to have a scratch and more often than not the wooden post and rail fence is ideal. This causes the wooden uprights to be pushed outwards and ultimately can cause them to break.
Even worse than scratching is wood chewing and wind sucking , fortunately not all animals do this but if let unchecked it can ruin a fence is a few months.*
A simple line of electric fencing rope on ring insulators can stop the animals from ruining the fence. Ideally this wants to be powered from a mains electric fencing energiser so it can be installed and be more or less maintenance free.
New fences are especially susceptible as it can take some time for the upright posts to bed in and the soil to be fully supporting.
Additionally this type of kit can be used to keep livestock ( usually horses ) off barbed wire fences. This will only work if distance rings are used.
* If this is the problem please call as you will require a slightly more involved set up.