I have several ages of chickens mixed together in one flock. adult to 14 weeks. they are all about the same size but i did not realize until today that layena is bad for the youngers ones. the 14 weeks olds have been eating it since about 11 weeks that means at least 3 weeks of a mostly lay crumble diet with treats and free range things mixed in. if i take them off the layena immediately is it too late to avoid organ damage? is organ damage from excessive calcium a certainty or a possibilty? so far everyone seems healthy and happy.