Nest box floor space?

[Chucken]

I am drawing up my plans for the wall that will have the external nest boxes mounted into it. I have space for two nest boxes (for 4 hens). For what I am planning, each box would be 15 ½” wide X 12” deep (or as deep as I want to make it). Is this width OK or is it too wide for them to feel secure?

 

[LarryPQ]

It will be just fine. When you gotta lay an egg, you gotta lay an egg. When the time comes, the hens won't care.

Here is my main nesting box:

With additions seen in the video in the first post:
http://thehenway.com/