By playing some simple games like fetch with your dog, you can kill 2 birds with one stone. First is that the actual playing of the game will surely tire them out so much that they won’t have the energy to jump the fence. Second is that you are associating the fun of the game with the yard. If they have fond memories of the yard they will be less likely to try and get out.
While the idea of "training" may seem daunting, it is simply teaching an animal what behavior works or doesn't work through resulting consequences — so whether you realize it or not, you are actually training your dog every moment of the day. Fortunately for you, preventing jumping is possible even without structured training. There are some simple solutions to this problem that require minimal effort and fit easily into your normal interactions with your dog.
Before you answer the door and welcome guests, clip a leash on your canine, preferably to a front-clip harness or head halter, so that he can be controlled in a manner such that he cannot greet if he jumps. When your dog is calm, with all four paws on the floor — which may take up to a few minutes for more excitable dogs — allow him to approach guests and say hello. If he jumps, gently turn and lead him away; wait for calm behavior before approaching again. For particularly excitable dogs, another option is to remove the dog to a contained area before guests come in. An exercise pen or baby gate is adequate containment for many dogs. If you have an athletic or large dog that can easily scale a gate, use a crate or move him to a room with a closed door. Once your dog calms down, clip on his leash and allow him to come out and greet your guests.
3. Because they have been rewarded for this behavior in the past, whether purposely or unknowingly. Some owners may, at one point or another, allowed the dog to jump on them or on their furniture, welcoming their dog's enthusiasm to see them. Other owners inadvertently reward their dogs jumping, simply by doing something good--such as walking or feeding the dog--right after the dog has jumped. Even if they told off the dog for jumping, by providing the dog with a walk or with food, they make the dog connect these positive actions, with a not-so-positive action: jumping! The dog sees thing in a very simple, linear fashion: if he jumps, he'll get to go for a walk--or even better, he'll get fed!