I got my first egg yesterday! So now, my question is are my chickens going to get enough calcium from the layer feed or do I need to suppliment? I have been saving cleaned egg shells and wondered if I can pulverize these and put them in the feed. Would this be enough or do I still need to purchase oyster shell? Now that I've switched to layer feed, do I need to provide grit or will my girls get enough from scratching around in the dirt in their run? Thanks!