(a) All feedstuffs used in the commercial production of livestock or poultry in this state are exempt from the state compensating tax as levied by this subchapter.
(b) As used in this section, "feedstuffs" means:
(1) Processed or unprocessed grains;
(2) Mixed or unmixed grains;
(3) Whole or ground hay;
(4) Whole or ground straw;
(5) Hulls, whether or not mixed with other materials; and
(6) All food supplements, whether or not nutritional or medicinal, including hormones, antibiotics, vitamins, minerals, and medications ingested by poultry or livestock.