Tiny tiny eggs - what's going on?!

[arr36]

My trusty cream legbars who always lay beautifully in their nestboxes have this week laid two miniature eggs on the floor of their run. I can't work out why! The eggs are identical in colour and texture to their usual eggs so I don't think it's another bird (and there are no nests nearby). Any ideas what's going on??

 

[Wyorp Rock]

Looks like it could be a "fart egg".
There are several threads here on BYC about them.

https://www.backyardchickens.com/t/929229/fart-eggs
https://www.backyardchickens.com/a/common-egg-quality-problems

 

[aart]

Could just be a glitch....happens sometimes.
Funky egg sometimes surprise them, don't 'feel' the same,
and they don't get to the nests before they pop out.