Goodness gracious! I know my eggs are delicious, but come on already! I've noticed lately that my cochin hasn't been laying like normal. Typically she lays every other day. Now I'm lucky to get one a week. Then I noticed egg shells under the big oak tree (on the other side of the six foot privacy fence that my girls are enclosed in). I am very diligent about checking the nests and my girls aren't laying after night, so something is going in there during the day and taking them over/under/through the privacy fence. Today two eggs turned up missing (I heard my cochin sing her egg song when I was in the shower, when I got out there fifteen minutes later the egg was no where to be found). AND one of my ceramic eggs is gone. What is taking my eggs in the middle of the day? While I'm home!? We have a rat problem (I've been trapping and baiting like crazy, they're starting to thin out now). I also noticed a crow hanging around these past few days. I live in the suburbs -- not to say raccoons and possums are impossible, but during the day?
My girls free range during the day but they have an open-fronted coop they go to lay in during the day.
You might want to look into roll away nest boxes. Or maybe put chicken wire over the open front of your coop, leaving them a small opening to get in and out.