Nest box design, size, shape, and material of construction have been a matter of preference. A standard box is approximately 9" (h) X 6" to 8" (w) X 6" to 7"(d) with an entry hole of 2 inches diameter.
The depth of the box is one of preference but should be no less than 9 inches high as shallow boxes encourage chicks to leave the nest early.
Click here to see pictures of a breeding box set up with nesting box and more. How to set up a Breeding Cage Plus