I'm looking into getting a few hens for my small back garden. I live on the outskirts of a fairly small town in the UK. My garden is bordered on two sides by a brick wall, and the third and fourth sides are enclosed partly by buildings and partly by wooden fencing. I intend to let them free range in the garden, and was wondering how best to make it chicken and predator proof. The walls and fence are a little over 1.5 meters, and the fence is made of overlapping wooden slats