Candled at day 4. Not seeing a whole lot

[Mother-Hen-Michele]

Yes, waterproof is better

The shell needs to breathe, so I would not paint it, but a little note to help you keep them safe is reasonable.

 

[Fwoof]

Is it safe to use a Sharpie on eggs? It’s so hard to see pencil.

@Duckduckgoosie, I would advise against using sharpie, since the lines it makes are so thick and it isn't exactly nontoxic.
I use pencil and read the eggs with a flashlight, but if you prefer using something thicker, you can use a crayon.