(a) This chapter shall not apply to any commercial feeds that have been manufactured or produced by any person, partnership, firm, or corporation for the purpose of feeding his, their, or its own domestic animals, livestock, or poultry.

(b) This chapter shall not apply to any commercial feeds whenever the purchaser of such commercial feeds desires to waive this chapter in regard to a particular manufacturer, seller, or producer of commercial feeds and the manufacturer, seller, or producer agrees to waive this chapter. No valid waiver may be executed unless the owner of the domestic animals, livestock, or poultry owns an interest in the feed manufacturing concern or the manufacturing concern owns an interest in the domestic animals, livestock, or poultry. The waiver shall be in writing, signed by both parties, and filed with the department. At any time after the waiver is on file, either party to the waiver may direct, in writing, that the department withdraw the waiver.