Calluses are the body's natural reaction to prolonged pressure on the skin. If your dog lies on a hard surface for long periods of time, he can develop calluses. They are most often found in large, heavy dogs and are generally just an aesthetic problem. Some dogs simply like hard, cool surfaces like wood, tile or even concrete. A thick-coated northern breed like a Husky may find a hard, cool surface preferable to a soft, warm one especially in summer.
Most dogs welcome a well-cushioned bed to sleep on.
A nice, soft couch or your favorite chair is also very nice if a dog bed isn't handy. There are many softening lotions and creams on the market made especially for dogs. The problem is that most dogs lick them off before they have a chance to work. If you do try a softening product, try working it into the calluses really well. Then find something else for your dog to do so that he cannot sit and lick the product off.