Hi I found this on a website and was wondering if it would be ok to do. "You can supplement the grit with finely crushed egg shells. To do this, wash the egg shells and allow them to dry completely. Then finely crush the shells with a rolling pin or pulse a couple of times in the food processor. The aim here is to provide a variety of grit sizes for the chickens." I also found this "As an alternative to Oystershell grit, you can bake crushed egg shells in the oven for 5 to 10 minutes until they are crisp." Any advice?