I have two golden comets that lay every single day. They are on layers crumbs and have free range in the garden. I also give peas and corn and feed them healthy treats like lean beef and scrambled eggs. I have been feeding eggshells back to them daily as I know creating eggs is a huge drain on calcium, and I'm diluting the crumb by giving other feed. I only feed them their own shells that I have sterilised in the oven. I have been doing this daily but wonder if it's too much. I read you can cause phosphorus imbalance. My girls are healthy and the eggs are hard shelled and perfect with no lumps, bumps or powder