I'm sorry if this is the wrong place for this thread, I'm still a bit new to this forum. We have 7 week olds, 9 week olds, and 11 week olds. We sometimes let them out for a bit to eat grass and we decided we had better get grit. I have heard that granite and oyster shells are good but our local feed place didn't have that. All they had was #1 and 2 silica grit and coarse limestone. We bought the limestone because we had never heard of silica. The clerk said the limestone is what people usually buy. Then after I read on this forum that high magnesium limestone is harmful to chickens. We don't know whether this grit has low or high magnesium. Should we be worried?