I know I'll get a wide range of answers to 'how many nesting boxes should I have?'... so let me just ask this: Should 1 nesting box per 2 birds be sufficient?
I have 5 nesting boxes for 16 current layers. They use two of them. Now granted they are big nest boxes and I see two and three girls in the same box sometimes, but the silly things just want those boxes, none of the others. 1 box per 2 hens should be more than needed.