My Female 'labish' Is 30#, 10 Years Old And Basically

My female 'labish' is 30#, 10 years old and basically in good health. She in the past month has loose to very loose stools that seems to not go away. She eats Pedigree beef chunks morning and night and has Wilderness chicken 'kibbles' in self feed dish. Snacks are mostly for lunch and consist of 1 Milk Bone (small size) and 2-3 Milk Bone Hot Dogs. Very little table food.
There have been no changes in our daily routine but this has appeared. We mix the Pedigree with cooked rice both times daily.