Multiple dog problems?

Question
Hello again, I have the female blackj lab and the male jack russle terrier, "Hallie" is going to be spayed at the end of this month... not sure if I'm going to get "Luke" neutered, anyways they are always running around biting each toher, hallie drags luke around by the neck sometiems and even lifts him off the ground, they stop for some periods but always seem to get back to it as soon as possible, sometimes luke gets mad and bites hallie hard and she squeals.... is this supposed to be like this? is there anything I can do to calm them down sometimes?  

Answer
Spay/neuter may settle things down.  A few years will help.  Here is a picture of a couple of carefully bred young dogs.  The lab is now working as a dog guide, and the Shepherd was selected as breeding stock, http://www.photolocker.net/images/Labman/gretchenandellaplaying.jpg  On a previous visit, we found a broken window within 5 minutes of the Lab coming in the door.  We had a yellow Lab at that time.