As I desperately need to mow and weedeat my dog yard, I'll also start puppy proofing it. Here are some hints for you, too.
It may not make sense to you that the same dog that is so happy to see you when you get home may want to find his way out of the back yard to freedom, but many dogs are lost each year because of this. Most dogs do not have a good sense of the dangers cars represent. Once outside your yard, they may just follow interesting scents and be so focused on those they aren't aware of approaching vehicles. They can also get frightened and run right into traffic. Many are efficient diggers. They can tunnel under a wooden fence with ease. With puppies, only a few inch gap between slats can be enough for them to squeeze through.
A back gate that is not latched properly can also give your dog an escape route. In order to prevent unintentional opening of any gate, secure the gate so that it cannot be opened from the outside. Make the latch inaccessible or put a lock on the gate and keep the key handy in the house. I have heard horror stories of neighbor kids letting dogs out and people stealing puppies right out of the backyard.
You need to do is check the perimeter of your yard for any gaps in the fence. One easy solution is to dig down six inches below ground and affix narrow gage wire fencing material to your existing fence. You can hold the fencing in place below ground by burying bricks, rocks or pavers. This will make it more difficult for your dog to tunnel under, and have the added benefit or making it harder for rodents or snakes to get into your yard. You may also want to padlock your gate. A strong dog may try to push open the gate, and some gates with loose latches can even be blown open by the wind. Keeping your fence in good repair is important. If the dog can find a loose or weak slat to chew through, he will.
I do not recommend Invisible Fencing. Other animals can still attack your dog, and someone could easily walk off with your dog. And they can cause real yard aggression issues. Think out it – every time someone or something goes by, your pup goes to investigate and gets an electronic shock. Soon he will associate the people, kids, bike, dogs, etc with the shock. NOT what I want to teach my youngster.