I have an egg-eating problem. In an effort to curb the habit I'm thinking of darkening the nest box and "hiding" the eggs by making the opening to the nest smaller. Our design is just like this one, built off the back of the coop with a slanted lid on hinges: https://www.backyardchickens.com/images/coops/monica/honsehus7.jpg It is 24"l x 24"w x 24"h with a divider in the middle. The opening is just an opening cut in the wall of the coop the same size - 24"x12" with a small lip to get in. I have a Barred Rock, Columbian Rock, RIR, Silkie and bantam Cochin.