My parents have a rottie mix that's around ten years old and she has been having hip/joint pain. My parents have been feeding her pedigree all her life. They finally decided to buckle down and switch to a better quality food on top of giving her supplements for her joint pains. I know money is limited a little so I was trying to decide if blue buffalo might be good or if even kirkland has a senior dog food that promotes joint health. Advice?