The Chicken Soup is infinitley better than Pedigree.
It's not just what is in a dog food that makes it good - what ISN'T in it can be even more important. It's going to make a real difference for Shelby especially. Her system just doesn't need to be taxed with dealing with foods that are hormone, chemical, toxin and disease laden. The closer you can get her to food made from human grade, organic (not natural - that term is meaningless) the better her chances. Try mixing her kibble with things like yogurt, mashed sweet potatoes, beef hearts, a spoonful of tomato paste, etc. Those are much better things to add to your dogs' diet than most canned dog foods. Stay away from liver and kidney for Shelby, as these are the organs that filter out and retain toxic substances and you want to keep as much of that out of her system as possible.