My hens used to be completely free range, but due to the rise in predator problems, they are always kept in the coop now. We are in the process of building a run, but it isn't completed yet. They aren't getting enough sun or calcium right now. They still healthy, nice bright combs, shiny feathers, laying on a regular basis, but their egg shells are getting softer. (The coop does get sun, and they get fresh veggies and grass on a regular basis, just not as much as they were used to.) At wal-mart, I found a reptile calcium ascorbate/vitamin D3 powder supplement. I was wondering if that would be acceptable to add a little to their food to help comp for the lack they are getting naturally? I've tried giving them oyster shell, but they won't eat it. They never have, even when I was having a problem with shelless eggs, they wouldn't touch it. So maybe this would give them the calcium they need. What do you think? Would this be safe to try?