I mixed instant rice with brown rice and now my dogs have rice in their poop is it bad for them?

Brown rice has more fiber in it, so it stays in the dog's digestive system longer, your dog stays satisfied longer, and the brown rice is digested more completely. The instant 'white' rice has had all of the nutrients taken off of it during processing. So, it shoots right through puppy's system, undigested. Brown rice is better for your dog and better for you. The other type is cheaper, but you get what you pay for.