I've seen some posts about hedgehogs eating eggs (both cooked and raw), but I introduced mine to a bit of an eggshell with some of the raw whites in it, and you know what: she wasn't interested in the whites. She started chomping on the shell.
I stopped her, but I wonder: is she interested in the shell only because it reminds her of chitin, or is it really good for her? Does anyone know?
Almost all animals will eat eggshells if they have a chance and it is not dangerous in any way.
An eggshell contains two layers; the outer layer consists of calcium and other minerals, the inner layer is made of chitin.
If an animal is low on calcium, it will eat eggshells or other sources of calcium.
If an animal is low on chitin, it will eat food containing chitin like eggshells (chitin is the material claws and fur is made of).
Eggshells are not dangerous for hedgehogs; if the amount of eggshell eaten is higher than the hedgehog needs, then it is not absorbed and is removed from the body in the natural way.
Avian (bird) eggshells are almost entirely composed of calcium carbonate, which is non-toxic and serves as a great source of mineral calcium. If you were to buy calcium supplements in pharmacy, they are almost guaranteed to be calcium carbonate as well (but also mixed with fillers to help forming pills). Upon consumption, it is also acting as a pH buffer which decreases stomach juice acidity by increasing its pH. Animals, and humans as well, can somewhat sense their own nutrient deficiencies and have according carvings for things which are not considered edible.
Actually, there is a condition called pica which is appetite for seemingly inedible things. Pregnant women are common to experience it. For example, if one has compulsion for crunching ice cubes, that could signal iron deficiency but there is no rule. I know of a case of animals (domesticated pigs) eagerly eating amounts of charcoal without ill effects. Sometimes it could of course signal deeper health problems, and you should prevent your animals from eating obviously poisonous things. However, eggshell cravings are common and I could only suggest you to consider grinding them into a powder to enable easier consumption.
