I honestly am not able to see much in mine. I do candle but just watch the size of the air sac, it should get bigger over time with developement. If it isn't growing it's usually a dud. I've heard of some people being able to candle but they're usually using a home made candler like one from a projector or something. Good luck with the Marans they are my addiction
Pitch dark room, high lumens flashlight, homemade thingy to close out all light except from a 1 inch spot CLOSELY fitting the egg. Then maybe you can see shadows around Day 14. Patience, Grasshopper!