We have gone to grain free kibble for most of our dogs. One of our problems is a couple of our really old dogs have digestive issues and get explosive diarrhea if they are not on a certain prescription food.
For our very old dog who really doesn't absorb any food or nutrients I just made her lightly cooked turkey, rice, green beans, and pumpkin and I put yogurt on it for probiotic. I'm trying to get her to gain a little weight and heal her gut a little. I'll cut back on the rice next time I make it. So far I'm having good results. She also has no teeth.
What I would like to do ideally with my not elderly dogs is raw feeding, but it seems too much right now with how many dogs we have. It would be nice to get Vet guidance to know that we are meeting the dogs needs and have support if needed, but it doesn't seem like our vet is into that.