If a bird food contains sodium nitrates, call the manufacturer and ask for some information on the amounts used and the safety precautions taken regarding birds. Tocopherols function as antioxidants, preventing the oxidation of fatty acids, vitamins and other nutrients. Manufacturers are using tocopherols more frequently as preservatives, as many pet owners are more concerned about chemical preservatives. However, tocopherols have a very short shelf life, especially once the bag of food has been opened. Ascorbic acid is a synthetic form of vitamin C. Biotin is a natural B complex vitamin.
Calcium carbonate is a natural form of calcium.
Calcium oxide is a natural form of calcium. Calcium pantothenate is a high potency, synthetic source of vitamin B5. Calcium phosphate is a calcium salt found in or derived from bones or bone meal. Chloride or Chlorine is an essential mineral, usually found in compound form with sodium or potassium. Choline is a B vitamin found in eggs, liver and soy.