Let me start by saying this is probably one of the most popular questions I get with customers at my job: How do I introduce my puppy to my older dog?
No matter what, there will be jealousy between the dogs. Especially if your dog is the only dog you have at your home. A way around this is socialization. This is as important when their puppies as it is when they’re adults. Relating back to my previous post on dealing with separation anxiety, dogs that aren’t properly socialized are more susceptible to becoming fearful of new people and situations. Getting your dog familiar with having other dogs around and people they may not know helps ease anxiety in the future.
Once you’ve made sure your dog is properly socialized before taking in a new puppy, it’s important to shower your older dog with lots of love when the puppy is around. It’s not uncommon for dogs to develop jealousy towards their new brother or sister. Although new puppies need lots of guidance and attention, make sure you involve your other dog in as much of the activities as you can; doing so will help alleviate the potential for either dogs to begin resource guarding you for attention.
This is the important part: introduce them to each other somewhere outside of your home. Your older dog has lived with you and has gotten used to having their own space. When you invite another dog in their home, their territorial instincts start to kick in and most of the time the meeting doesn’t go well. I’d suggest taking them to an open area such as a park or even in your own backyard. It’s important that when they do meet that they both have the potential to get some distance away from each other if they grow irritated of each other.
Once you get past this phase doesn’t mean you can let your guard down; there will still always be a battle for dominance. Dogs are pack animals and you are the pack leader. You’re expected to treat them fairly; if you give one dog a treat, the others should also get the same treat. It takes a lot of work to balance more than one dog at a time, but it can be very rewarding to have twice the amount of puppy love.
A Pup's Life 