He (they...I have two) don't eat commercial dog food. I actually cook for them. Aside from it being better, it's actually just as cheap. In any event, I change from whole roasted chicken to rare beef to salmon or a mix of all three. I also mix in "Veg-to-Bowl" by Dr. Harvey. It's simply human quality dehydrated veggies of all kinds that you rehydrate w/ hot water. While their coats are great, I think I may have made them somewhat micro-nutrient deficient b/c I neglected to add various minerals, etc. I will give your suggestions a go and see what happens. For now I will wait on the ultra-expensive cardiologist appt. b/c he doesn't seem like he's an urgent case right now. If it progresses or does not improve, I'll have to take him. He's such a good boy. Cute too.