Cackleberry is the humorous American-English slang for the egg of a hen or domesticated fowl.
It is a compound word of the verb ‘cackle’ to utter the “sound a hen makes, especially after laying an egg” and the common noun ‘berry’, the fruit without a pit.
The earliest written record of “cackleberry” can be found in the menu of the annual banquet of Oakland Country Club published in the Oakland Daily Evening Tribune on 2 February 1889.
The expression was most used between 1918-1933 but since then it has still been part of everyday language, though not that popular as in the beginning of the 20th century.
On Deliveroo one can order “Half Dozen Cackleberry Farm Eggs” and you can find hundreds of “cackleberry recipes” on Pinterest.
Atari Corporation released an LCD style game for Atari Lynx named Eggsavier’s Cackleberry Rescue 2020 in 2019.