I would grind the shells up to help them in digestion and keep them from getting stuck. Some ppl like to microwave them for a few seconds to kill any bad bacteria that may develop while storing. I've been saving my shells for a couple of months waiting for that first egg. I will then crush, zap and feed them. I also start my new chicks on mashed up boiled eggs on about day 3. Good Luck
Right after this post i went out and found my first egg. Had to run to feed store and buy layer feed and made a small feeder for eggshells. They are just looking at the eggshell not sure what to do with it.
I was just wondering how young you could start giving them boiled eggs... I gave mine a little bit of mashed up hard boiled yolk the other day and they went nuts over it! They were about a week old. Hmmm, maybe I'll cook them an egg today, lol.