I have 6 standard pullets and one splash silkies. I am building a larger coop and this old bookshelf that I want to make a nest box out of. If I turn it on its side as I planed I would get 2 nest boxes out of it with the existing on existing self separating the two nest. Each box would be 13"L x18"H x12"D. And if I put a divider between the shelf and the two sides I would get 4 nest boxes out of it. However if I do the latter each box would be "13"L x 9"H x 12"D. I know it sounds a little confusing but if anyone know what I'm trying to convey makes scents to you then my question is. With 7 hens is two nest boxes ok and if I need to make it a 4 box is the height too short for them to want to use the boxes. Here's a rough sketch I made. I hope it is clear enough.