My 20+ week old hens just started laying last week. I was worried since they were on grower still and not on layer feed with extra calcium that the shells would be a little brittle or soft...well I was wrong. I've gotten about a dozen in the past week from the two that's started laying, and the shells are hard to crack, even on the side of our cast iron skillet. I've never seen shells that thick and hard before. I think I found out today why the shells are so hard. My land is very, very "crawfishy". It is clay soil and I get the crawfish mounds all over the yard, and of course in the uncovered portion of the chicken run as well. It stays wet in the winter. While I was in the covered run area today fixing a feeder, moving the water dish higher, etc, I kept noticing behind my back the hens chasing each other. When I finally got up and turned around one of the Red Stars had her head back choking down an eating-sized crawfish. I watched them for a little bit and they have figured out to wait on the crawfish to come to the top of the hole, and they pounce on them and pull them out. Then the chase is on until they can get it choked down. I was wondering why they have been eating a good bit of grit lately, trying to get those things chopped up lol. Anyway, just wanted to share.