I have a flock of 13 hens, all 1 year-old last week - Barred Plymouth Rock, New Hampshire and RC Brown Leghorns. The NH always had the nicest shell quality (with a sheen) and the BPR the dullest shells, but lately (the last month), I've noticed a decline in shell quality with a lot of the eggs. Some have uneven, missing spots or dark spots of pigment (not the leghorns white eggs, but the brown ones). Many (including the white ones) have little small raised areas of excess shell, and even the NH's seem to be losing their sheen. I have not changed feed, but they are back to using a large yard (1/3 acre?) where they spend most of their time. They have access to oyster shell and seem to go through it fairly quickly. Surprising, that they crave the oyster shell, since their feed is a complete feed (with calcium and 19% protein). They seem to be eating less of their feed now that they are ranging again. I did not have many shell issues in the fall, when they were completely free range (but, of course, just beginning to lay). They have been laying at 80-90% for the last month, so maybe the production is somehow getting ahead of the nutrition??? In the last few days, I've seen a drop-off in production, but that could be temporary.
