My 20 laying hens were struggling this spring with decreased laying and weak shells. I have tried to get them to eat oyster shells but they won't. I reached out and found an idea of mashing up their eggs and feeding it back to them. I also found information about feeding them yogurt. So I combined the two with great results! I put the eggs shells in the microwave for a few minutes to kill any bacteria on the shells, then I put the in the blender to make the shells super fine (I don't want the girls to get wind of the shell and start going after their eggs). Then I add a 1/2 cup of Greek yogurt serve it up. They eat it so fast and their laying increased with nice hard shells. No egg eating either. I hope this helps other fellow chicken enthusiasts I am not sure if there are any issues with my method, but so far no side effects other than happy chickens.