The answer is, gradually. Things may not be so bad when you already have one or more adult dogs at home and are bringing in another adult dog. On the other hand, introducing a puppy to a home with adult dogs or an adult dog to a home with a puppy may be an entirely different story.
At no time from the get-go should the dogs be allowed to mingle. The new dog needs some time and space to become acclimated to its new home and perhaps sleep or eat quietly. Ideally, you can use a spare room and provide a dog bed, dish of water and food for your new dog. Once your new dog has had some time to adjust to his surroundings, you should allow your dogs to be in each other's company, gradually at first. I don't think that you'll be able to predict the results of this meeting, given the sizes, breeds and ages of your dogs.
Life is hard
2 years ago