I am pretty sure, can’t find the shell of the one i cracked so far. Others haven’t been used quite yet. I think housekeeping may have thrown the shells away not realizing that i save them, because what weirdo saves egg shells?!?!?! Hahaha. <— this weirdo, is the answer to that query

I looked at it and it was definitely light in color on the inside. Blue/whiteish, but not brown if brown would be an option.
The two BYM i have may or may not have hatched from olive eggs and would have come from a BYM roo and OE hen. I incubated 4 brown, 2 olive eggs got 100% hatch and then lost some in the fire we had so I’m not sure who hatched out of which eggs because the ID bands have long since melted or have been otherwise picked off.
For anyone following trying to figure out eggshell colors (chicken geneticists please jump in here as needed):
All chicken eggshells start out either white or blue, same color inside and out. The blue is a result of a genetic mutation long ago (triggered by an RNA virus, if I recall correctly) that produces a shell pigment called oocyanin. This pigment originally was found in some South American breeds, including the honest-to-goodness Auracana and Ameraucana, and now also in Cream Legbars, which were bred partially from Auracanas in order to get the blue egg gene.
If there aren’t any genes for brown eggs in the hen, her eggs will be either white or blue.
If the gene for brown is present, the shelled egg then gets X amount of brown pigment deposited on the outside (only) near the end of the laying process, and the amount of brown pigment determines the overall color. (This process is often jokingly called the “spray paint booth” on BYC.)
If the egg started out
white, any brown pigment applied will result in eggs colored pink, beige, tan, medium brown, and up to chocolate brown, sometimes with speckles.
If the egg started out
blue, any brown pigment applied will result in green-blue, green, olive green, and up to a deep rich olive green, with or without speckles.
My fascination with this is behind why I’m always asking what color the inside of an eggshell is!