
1. Keep it friendly - It may be possible to introduce the dogs in a relaxed manner by just letting them sniff and play, as long as both are known to be friendly with other dogs.
2. Take it slow - If you are not sure how the dogs will react, start off cautiously by taking them for a walk together on neutral territory (e.g. a park, not your yard). When they show friendly behavior toward each other or begin to ignore each other, move the exercise to your back yard. Finally, allow the dogs to be together in your home.
3. Watch for signs - Be aware that wagging tails do not necessarily mean that dogs are happy to see each other. A straight up tail that wags stiffly is a dominant sign that may signal aggression. If one dog's tail is tucked down between its legs, that dog is afraid and nervous. This calls for a gradual, well-supervised approach to avoid making the dog even more fearful. If a dog's tail is horizontal and wagging in a relaxed fashion, it's all systems go!
4. The dominant dog will emerge - When the dogs eventually meet off-leash, one of them is going to need to establish dominance. This is a normal and necessary step in a dog-dog relationship, but sometimes the process can look and sound pretty scary. The dogs will maneuver around each other and may even scuffle to the point at which one dog ends up on his back, with the other dog standing over him. There may be some nipping and grabbing of the neck or throat. Try not to worry too much when this happens. It is normal for dogs to engage in such roughness. Once the dominant dog establishes himself, he probably will not feel the need to repeat these maneuvers.
5. Support the dominant dog - Once the dogs are together, make sure that you support one dog as dominant (this will probably be the resident dog). Show him that he is number one. He should be fed first, petted first, given attention first and given the favorite sleeping area. Do not expect the dogs to share. Sharing is not normal for most dogs. Feed the dogs separately (across the room) and do not give really delicious chew toys (rawhides, pig ears) at first. Once the hierarchy is secure, you will probably be able to give the dogs all the chew toys they want.
Introducing a new dog into the home can be a lot simpler when it is done correctly. Do not get upset when the resident dog tells the newcomer to "bug off." This is how the new dog learns the house rules. Eventually they should become fast friends.
If you are thinking of getting another dog - think about the related costs and make sure that you can afford it. Some people think it is just a matter of buying a little more food, but it is much more than that. Having a dog is a BIG responsibility and it can be very expensive. When you increase the number of dogs, you also increase your responsibilities and costs. At a minimum, a dog costs you between $600 to $1,000 or more each year. Costs increase if you board your dog or if your dog has medical problems - and as we all know, medical care can be very expensive.