Tiny egg, my hes are all 9 months old, has been laying large to extra large eggs. Today I get this tiny egg, why?

[Vjenkins]

 

[FrostRanger]

Looks like a fairy egg. They happen from time to time, nothing to worry about, just a random glitch in the system

 

[sourland]

Sometimes, it 'just happens'. Generally at the beginning or end of a laying cycle.