I read somewhere that if marans Exposure to sunlight or there eggs were undersunlight or anylight will lighter the shell eggs color..
is that true?? and is there any tips could i do to make shell darker
From what I understand shell color is genetic. If you got your marans from a hatchery, then they have most likely been bred to have a higher egg production but the eggs arn’t as dark as a result. The hatcheries have made a median between egg production and egg darkness which is usually fine for the every day backyard keeper.
And as for sunlight, it would take well over a month before you even saw the slightest change in color