Over the last month I have noticed that my Australian Shepherd (8 Years old) stomach is getting bigger, I have cut back the amount of food that I was feeding him but that don't seem to make a difference. I had noticed that he was in the corner of the yard eating dirt, so I went to the pet store and bought some Pet Tabs for older dogs with special needs. I haven't seen him eating dirt any more. He seems to feel okay, has a wet nose and is eating all of his food everyday. His stomach is very firm on both sides, looks swollen and it does not seem to hurt him when I touch it. It seems that he is bowel movements are fine, I have looked for signs of worms. Do you have any ideas what might be wrong with him?