I have had oyster shell available for the girls for a year and they have hardly touched it but the past month they are really chowing it down and don't know why. Still feeding them Layena like always,even when I was feeding flock raiser during the summer due to mixed age flock the ten older girls barely touched it. Just can't see the reason for the uptick. All the older girls have gone through molt and all but one has resumed laying but she is getting close. Anybody else seeing this in their girls?