I'm not sure there's anything you can do to prevent "gritty" eggs. I've got one hen that consistently lays eggs with little bumps like that one one end. My girls have grit, oyster shell, excellent quality layer pellets, lots of treats, and Avia Charge 2000 in their drinking water! I'm not sure if I can give them anything else!
I only have 2 customers who get a dozen eggs each week. Both of them are folks I work with, and both of them think the unique eggs are the neatest of all! In fact, they open the cartons as soon as they get home to show their kids, who just marvel at all the differences in shape, texture, etc. They're all the same inside, and it's been a neat lesson in diversity for the kids!!
I only have 2 customers who get a dozen eggs each week. Both of them are folks I work with, and both of them think the unique eggs are the neatest of all! In fact, they open the cartons as soon as they get home to show their kids, who just marvel at all the differences in shape, texture, etc. They're all the same inside, and it's been a neat lesson in diversity for the kids!!