Here's the background story. I have 8 older hen that are over 1 1/2 yrs old and we have 12 pullets that are almost 3 months old. They are currently on fermented "All in One" crumbs because of the pullets. They get feed twice a day and are eating about 6 qts in 2 days. I've also been giving them one over grown zucchini every morning for the past month. Plus a hand full of scratch and boss seeds in the afternoon as a treat. They have been free ranging in a paddock for the past month too.Usually first thing in the morning and then again in the evening. Here's my dilemma. Their egg shells have been getting pretty thin and the past two days there has been a broken one. Normally I know this is because of low calcium but they have access to oyster shells anytime they want along with grit. We have even been mixing some oyster shells with their scratch once in awhile that is thrown on the ground in the afternoon.Just to encourage the older girls to eat some. Could my problem be from all the zucchini they are getting or the change in their food? The older girls use to be on fermented "Layer Food". Or is something else going on. I'm not sure what else I can do. Anyone have any advice.