RC has chondroitin and glucosamine which is very important for the joints. I've had no problems with the food but it is very costly to feed 4 Yorkies with it. Lately they like a few bits of cooked hamburg or chicken in it and they'll eat it better that way. They don't have shiney coats but all seem healthy. One tends to get overweight so I have to feed less food. One is a ball of extreme energy and the 28 ' of protein keeps her going.
Maybe they need a change to another brand just to get a different taste. Maybe like people, they'd like something different once in a while.