One of the keys to a healthy Cairn Terrier is plenty of exercise and meaningful work to do. We cannot stress enough that the Cairn is a working terrier. Everything about his structure, coat, and temperament has developed over centuries to locate and kill vermin in all kinds of weather. No surprise then, that the Cairn, and other terriers, have a very high pain threshold. If a Cairn pulled away in pain from an attacking badger or fox, the dog would die – either from the vermin attacks or from the human owner. No cowards or wimps allowed in a working pack of terriers! Therefore, the popular “invisible fences” should never be used to confine a Cairn. All the dog needs is to see a squirrel or rabbit beyond the fence boundary, and it is off on the chase. A puny electric shock will not stop such a determined hunter. In addition, any loose, aggressive dog can enter your yard with invisible fencing to attack, perhaps, kill your Cairn. Because many of us live in areas where fox and coyote abound, perhaps, even cougar and bear, your Cairn deserves a large, securely fenced yard with a dog-proof fence at least five feet in height to keep out predators. If coyotes or mountain lions are a real problem in your area, then “hot wire” the top and bottom of the fence. Documented cases exist of dogs killed by such predators that easily scaled six-foot fences. Hot wire is an economical way to protect both your Cairn and your children. Any gates on the fence should be secured with sturdy padlocks – not to keep the Cairns in, but to keep out the neighborhood children. Cairns and children just naturally attract each other – perhaps, from all the centuries of these terriers being raised in the Scottish Highlanders’ cottages with the family. Children regularly come in to play with the Cairn, but then they forget to close the gate or to latch it securely. Cairns love people, all people, and will happily trot off with anyone. Padlocks on the gates will ensure that you give the permission for children to play with your dog and that the yard gates remain closed.