Vital Essentials Freeze-Dried Raw Duck Hearts Dog & Cat TreatsDuck hearts are an excellent source of naturally occurring iron that helps support your pet's immune system; a perfect guilt free, single ingredient, raw protein treat for pets that deserve the best. Treat your dog to butcher cut raw protein between meals for a snack that builds strong muscles for more play, naturally supports digestive and oral health, and provides essential nutrients to support your dogs vitality.