Don't get all excited they're ceramic. They serve two purposes first they let the hens know that the nest boxes are a good place to put their eggs when the time comes and secondly they are very hard so when they peck at them they learn that eggs are hard nasty things and it hurts if you peck them, so when they lay their own they won't even think of pecking one, hopefully. If all goes well the first eggs should be arriving in the next 3 or 4 weeks.
