Well,

if its any constellation a lot of the "older generation farmers" around here swear by a teaspoon of dirt a day for children. It toughens them up

Then again I personally wouldn't eat ANY of the dirt around here because I know how full of crap it is (litereally from cows, horses, alapcas, dogs, pigs, sheep, cats, birds and yes giant earth worms)

I am wondering if you have enough vitamins in your diet actually because finely crushed eggshells can actually be very helpful for some minerals in different animals diets. Like duck eggs for eggsample (sorry couldn't resist) if their shells are super soft their diet is lacking in something and finely crushed eggshells in their food can help produce harder shells ( I saw it on Dr Harry)

Other than that, I would have to say that is the WEIRDEST craving I have ever heard of.

Nae x