(1) Each dealer and shipper shall at such times as by rule required file with the commission a return under oath on forms to be furnished by the commission, stating the quantity of dairy products handled, processed, manufactured, delivered, and shipped, and the quantity of all milk and cream delivered to or purchased by such person from the various producers of dairy products or their agents in the state during the period or periods prescribed by the commission.
(2) The commission has the authority to issue subpoenas for the production of books, records, documents, and other writings of any kind and may issue subpoenas to witnesses to give testimony.