As your Senior dog ages, his diet may need to be changed. A dog that is older may have trouble chewing hard dog food because of older teeth. He many need more water and liquid in his diet. Or he many just be pickier in his old age A great food suggestion for a senior dog would be to switch over to canned food. The added moisture in the canned dog food can help the dog to stay hydrated. You can also add some fresh food into the mix:
Too much of a good thing can upset his stomach. So be mindful of how your dog reacts.