Do you find that you need a non standard nest box for Orpingtons or other large chickens?
My husband is convinced that our Hens are not going to nest in a 12 inch ware box. My hens are not laying yet , but soon will be.
I'm not sure it matters that much if the box is larger than 12x12. Our Orps lay in a small dog kennel. We like the size - way bigger than 14 x 14 - and the fact that when they go broody we can pick the whole thing up and move them to a better location to raise the chicks!
Errr... I mean ducks. This year our broodies just hatched out duckllings for us.
What mine like the most is the darkest location they can find. We have 7 kennels with the chooks and they like to lay in whatever ones are in the darkest location and ignore the others.
My temporary coop has ben a large kennel but they were starting to fight for room. We got two rectangler dog houses at TSC and are refitting them with roost, and boxes and a smaller doorway. It seems to work. Like the thought of broody hens being able to be moved so easy with your ideal.