I've been reading, but can't find anything other than "free choice" as an answer. I finally went out and bought some oyster shell and offered it to the girls, because with 24 hens, they've apparently picked the place bare of any minerals and I'm starting to have issues with soft eggs. I brought it in and they taste tested and have been picking away at it. How much do they typically eat? A 5lb bag cost $6.36, and if they continue eating it like candy, I'm going to have to buy a new bag every week. I know that they will have to make up for the deficit from what they've been lacking, but really, on average, how many birds do you have and how much oyster shell do you go through per week or month? And, is there a cheaper place to get it than TSC?