No association organized hereunder shall be deemed to be a combination in restraint of trade or an illegal monopoly; or an attempt to lessen competition or fix prices arbitrarily, nor shall the marketing contracts or agreements between the association and its members, or any agreements authorized in this Subchapter be considered illegal or in restraint of trade. (1921, c. 87, s. 26; C.S., s. 5259(m).)