I have a flock (totaling 13) of orpingtons and faverolles less than a year old. They are laying VERY well! I am getting 12-13 eggs per day (not bad at all since we are in the middle of winter in Maine). They lay brown eggs. I have noticed that some of the eggs have darker spots on the top and bottom. The spots cannot be washed off - I have tried. The spots appear to be part of the shell not on the outside of it. It almost reminds me of the way ice on a pond looks - some areas are darker than others. I feed them Blue Seal Layer pellets and they have access to oyster shell as they choose. I must admit that I do spoil them with cracked corn on a daily basis and table scraps provided that it is not meat. I have this thing for vegetarian fed birds. Of course, if they find bugs or other things to eat in their environment that is just fine with me. Are the darker areas on the shells an indication that there is something missing in their diets? Or is it normal? If you have any information on this subject I would love to hear from you.