Whenever “cold storage eggs” are sold at wholesale or retail, or offered or exposed for sale, the case, package, box, or other container in which the eggs are placed or delivered shall be marked plainly and conspicuously with the words “cold storage eggs,” or there shall be attached to the container a placard or sign having on it those words. If “cold storage eggs” are sold at retail or offered or exposed for sale without a container or placed upon a counter or elsewhere, a sign or placard having the words “cold storage eggs” plainly and conspicuously marked upon it shall be displayed in, upon, or immediately above the eggs; the display of the words “cold storage eggs” as required by this chapter shall be in letters not less than one inch (1″) in height and shall be done in the manner that is approved by the department of health.