But that same argument works the other way too, no? If you define a chicken egg as an egg that came from a chicken, then if you have a dozen of eggs you cannot know whether they're chicken eggs or whatever eggs unless you know specifically a chicken laid them. Even if you take a dna test of it and it comes back as "a chicken", you cannot know whether it is in fact a chicken egg.
In the other definition you are capable of determining whether the egg is in fact a chicken egg by its contents.
Another very simple solution that will work well is just a google docs file that you share with people.