The Root of the Behavior
Other dogs attack their beds to help burn off pent up energy. Our dogs need daily exercise to truly thrive. It is good for their bodies as well as their minds. Dogs who are inactive can become hyperactive and destructive. Attacking his dog bed is but one way for Fido to use up all of that excess energy he's got inside of him. To avoid the problem of boredom, ensure that Fido gets a daily walk. Even if it is just a short one, it will help improve his focus and outlook immeasurably and will reduce any unwanted behavioral problems. Providing access to plenty of varied and fun enrichment toys will also help to keep Fido's brain engaged, so that he doesn't have the time or interest to chew on or attack things that you'd rather he not. It is also possible that anxiety is at the root of your dog's bed attacking ways. Dogs who are anxious exhibit chewing behaviors as a means to self-soothe. Of course, digging behaviors could also just be your dog's way of getting comfy! Just as we like to arrange our blankets properly to ensure we are warm and cozy, so too do our dogs have preferences for their bedding.
Encouraging the Behavior
Circling was also a behavior that was helpful to dogs in the wild. Ground in wooded areas is often not level, and it is uncomfortable to sleep on uneven surfaces. But more than this, wild dogs needed to remain hidden from view in order to afford their pack the best opportunity to survive. The act of tamping down the ground through circling levelled the ground but also created a slight indentation in the earth for the dog and his pack to nest in. This allowed the wild dog a small additional measure of "disguise" from the prying eyes of potential predators. But more than this, circling also afforded the wild dog a different vantage point from which to detect the presence of danger. If your dog likes to engage in attack behavior towards his bed, there are some measures you can take to help him with this. For some dogs, it is simply an instinctual behavior that is not harmful for them or their owners. If this is the case with your dog, it is not necessary to do anything to change it unless it bothers you.
Other Solutions and Considerations
Ensure that Fido receives regular exercise. A dog that has proper mental and physical stimulation on a daily basis is far less likely to get himself into trouble. If you cannot be home to walk Fido yourself, consider a dog walker or even a few days a week at a reputable, responsible doggy day care service. You did purchase Fido's bed for him to enjoy! If Fido using his bed for the purpose it was intended is important to you, you can begin by using a clicker and treats to shape the behavior you want to see from him. By lavishly praising calm and quiet behavior in his bed and filling it with toys that are a suitable match for his chewing habits, you will soon be able to teach Fido that his bed is for resting, and his toys are for chewing and never are the two to meet!