nesting box

Today, in anticipation of the Ventura Poultry Show and our future chickens,  I made 3 nesting boxes.  I was going to make 6 because I didn't know you only need one nesting box for every four chickens.  I do not plan on having 24 chickens so this should be plenty.

I've read that the boxes should be 12"x12"x12" at least.  My initial thought was to give them lots of space but I was also informed that they won't lay in the boxes if they don't feel cozy and secure.  The finished dimensions were 14" wide by 13" high and 12" deep.  The lip on the front is to keep all the straw or wood shavings from falling out.  Also, I got worried that I'd made the boxes too roomy and wanted to make sure the chickens feel tucked in.  I had enough wood on the property from previous owners to construct this without purchasing any new.