Younger Dog Aggressive With Older Dog

[halfbuck]

Hello everyone,

We have two, female indoor dogs. Both are mixed breeds (from the pound) and are aged about one year apart.

They are the best of friends 99.5% of the time. Playing with one another, sleeping together, etc. However, the younger of the two is becoming more and more aggressive toward the older at certain times and will sometimes jump on her and begin a fight. It most often occurs at particular instances. The most common are:

1. They both become excited when it’s time to go for a walk, and as we leash them and open the door and leave the house, they begin barking, and if they get too close to each other, the younger will jump on the other. They are fine once we are out and walking, although the younger definetely is a leash puller and tries to stay out in front.

2. If we are holding the older dog to check it for something, to clip her nails, just hug on her, etc., then the younger will become agressive and try to jump on her.

3. If someone comes to the door, they both become excited and begin barking. Once again, if they get too close....

When we can tell that the younger one is beginning to act "weird", we separate them a little to give them some space. Sometimes right afterwards, the older dog will begin walking around trying to avoid the younger one. All the while, the younger keeps walking along side of her at every turn and won't leave her alone.

It seems to be getting worse, with the incidents happening more often. I realize that we're probably having a domination issue, but I don't understand why it only happens during these specific events and she's "buddy-buddy" the rest of the time. I also don't know how to stop it.

Any help and ideas would be appreciated. Thanks!