I had to laugh and hard when I read that cavemen sat around all day!!! That was one of the most idiotic things I have ever heard. Dogs do have trouble digesting raw PLANT matter, but not raw animal matter. What a ridiculous argument for why processed foods are better for you.
My vet doesn’t like raw, but other than that, she isn’t that moronic.
Try adding a supergreen like spirulina, kelp, or alfalfa to your dogs food and see if that curbs the grass eating. It did for mine, but some dogs just like to graze.
