Yeah, I buy pretty good food for my dogs, and even then, barley is in the top 6 or 7 ingredients listed. It's OK for the dogs.
NO hops, though. There's a risk (not even close to 100%, but a risk) that your dog could have a genetic condition where eating hops will knock out their ability to regulate their body temperature. They can overheat and die.
Last batch of beer I made, I baked something like 5 cookie sheets full of dog treats and barely even made a dent in the 10 1/2 pounds of used grains. (Well, more like 20 pounds with the water weight...)