We have a few about those measurements, then down on the end we have one big one probably the equivalent of 3 of them. We did that because these silkies want to sleep in the nest boxes so we gave them a giant one and they use it, but still go lay in the nest boxes too.

Rarely do they lay in that big one, but they have. I beat them at their own game and put horse pellets in all of them. They didn't mind! Dang chickens! Well, at least I have cleaner eggs now and the only maintenance is stirring them once a week or so.