Found single egg

[CrazyBirdLady09]

Needing to know what kind of egg this is haven’t seen any more around but this one was in the pin we had our bird in.. it’s about the size of a quarter and the only other animals we have in the coop are ducks but they are done laying I assume because our female just got done molting and her eggs are always big and white not brown and round

 

[R2elk]

It isn't the right shape for a guinea egg. maybe a wind or fart egg of some sort.