That was my first thought, lack of calcium. My great uncle decided to get a bunch of laying hens. He is in his late 80's and thought he needed something to do since being retired for the 10 years was so boring... he still runs a few head of cattle and refuses to ever leave his farm for the retirement home. Anyway, we've had more eggs than I know what to do with bc you know Uncle Bruce didn't just get a dozen hens, no way he'd keep it simple, last count 68 hens. He has kept the entire family supplied or picking up eggs, dropping of cartons, running to the coop for feed and supplies. We are poultry producers now... I have to go up Sunday to clean out the coup and spread it on his garden.