This is what I do to the egg shells I feed back to my chickens. I wash out the remaining egg white and set the shell aside to dry. When I get tired of the pile of shells, I put them in a mixing bowl and crush them with the bottom of a glass. I aim for <1/4" pieces. Dump them in a container with...
Yup!
Do you have any leaves from last fall? You could put a layer of those in too.
Here's a way to tell if you have the mix right. If it gets warm and has a good "earthy" smell, it's going great. If it get slimy and smells, you probably have too much nitrogen. Add some leaves or dried grass or...