Don t throw these away I LOVE recycling eggshells back to my flock Not only does it reduce my need to BUY crushed oyster shell but my hens LOVE crushed eggshells They purposely pick around the oyster shell chunks to grab a piece of eggshell The KEY part of this whole process is drying them completely and then crushing them into small pieces You want the eggshells to no longer resemble an egg in any way form or fashion That s because once your flock figures out that their own eggs are a tasty treat it s all over Once they become e g g -eaters it s nearly impossible to stop Do you have to dry them in the oven Nope but it gets the job done faster especially during the humid summer months