You do need it, when just starting my ducklings out I sprinkle some grit on the bottom of the brooder if using towels if using shaving then you'd need to put it in a dish or the grit will get lost down into the shaving. Please don't feed your ducklings scratch they really need their peck starter it has all the nutrients they need right now, like needlessjunk said scratch is a treat. Brewers yeast is what you sprinkle over their feed to give them them the extra Niacin they need that's not in chick starter.