Pencil gets worn off really fast under a broody hen as well.
and I think Madrooster was joking about the whole lead thing seeing as how some are overly paranoid. Just guessing tho... But that was how I took the post.
pencil works good for me, although they could get led poisining , lol
PENCIL - Sharpie pens soak through and have toxic fumes. Yikes. Also, I misted my eggs a lot, they sat on papertowel - had wet chicks walking all over them - it does NOT smear. I do however use a mechanical pencil with #2 leads. The old style pencils (wooden ones) might have a different grade of lead that is more smearable.
No, there has never been any soaking through, leaching, or penetrating the shell here EVER or any evidence of "toxic fumes".
A Sharpie Permanent Marker is perfectly safe for marking 'eggs for hatching'.