I'm pretty sure it only provides calcium. I give Nova and Luka whole eggs, cracked but not broken and with the contents still inside. They eat it just fine. Mandy won't eat the shell unless if I grind it which is too much work for me so I just let her skip it. She gets enough calcium in her diet already. Buck had his first shell last night and he played with it for a few minutes and then finally ate it lol.