We got several cartons of “medium” brown eggs with what seemed like an unusually wide size distribution, so I picked out and weighed an assortment for future reference:

Of course, there’s an egg size specification. Actually, there are many egg size specifications.
We occasionally get huge eggs, tiny eggs, eggs with two yolks, no yolks, or blood-spotted yolks, all of which turn out to be no big deal. I admit to not previously encountering the term “fart egg”, however …
…the organic eggs, barn eggs, eggs from enriched cages…
https://munax.fi/identification-codes
Next New Thing: chickens laying RFID-tagged eggs!