Individual carcasses of poultry meat or packages of cut-up poultry or poultry parts need not be marked with class designation in any of the following cases:
Each shipping container shall be clearly and conspicuously marked with the proper designation of class, and of the intended use, in letters at least one-half of an inch in height, on a surface which is readily visible to the purchaser.
Ca. Food and Agric. Code § 26004