She eats the older dog’s poo, whom I suspect, like you said, is not digesting everything.
What is “raw”?
I feed it ground, many people feed it whole and breeders on my Natural Cocker list are weining their new puppies on whole raw -- slightly chopped.. makes for great teeth, much fewer vet visits and a lot healthier dogs and cats. Cats are more difficult to switch if they are older..
What do I feed? Beef, Goat, pork, rabbit, lamb, venison, etc., Green Tripe, steamed or purreed vegetables...the meat all has bone ground in along with organ meats and some tripe... the green tripe and some different things like tongue, spleen, pancreas, I get from Greentripe.com...
If you have a strong stomach -- I buy most of my meat from Hare-today.com in Pennsylvania.... check out their website... it's a raw-feeders paradise.