|Painted Hunting Dog|
taken through a wire fence
1. I would recommend a 300mm lens and up but this all depends on how close you can get to the fence, most places have a barrier stopping you from getting too close.
2. On full zoom try and get as close to the fence as possible, try and avoid any part of the fence that has direct sunlight on it because this will increase the chance of it showing up in your shots, so pick a spot that's in shade.
3.Manual focus on static subjects if your auto focus is picking up the wire, on moving subjects I use AI servo (continuous) focusing on my Canon 7D.
Hope this helps.
Thanks for looking.