Egg Carton Vent

[deerman]

Foam cartons natural vent, the foam will let air in or out.

Paper ones need to have vent holes.

 

[vermontgal]

I wonder if the "vents" are for structural rigidity of the cartons?

Both of the cartons linked above are paper cartons. As to breathing, styrofoam is closed cell foam. I don't think it breathes.