4 or 5 would be sufficient. I have heard some say four hens per nest box and others say 5 per box. I have 20 and have 6 boxes...they only use 3 of them and the cochin uses the fourth one as her very own potty (it is soooo gross). Not one other bird will touch that box. The other two just get forgotten.
I know this may be a stupid question but, Does it make any difference if the nest boxes are all in a row or stacked? is it better to have one row of six or two rows of three or three rows of two??? Do the chickens tend to use the lower boxes if stacked?
I don't know if it makes a difference or not. I think they pick the favorites and use those ones. My girls all lay in two boxes. I have four boxes, two on bottom and two on top they only use the two on the end top and bottom. Don't know why.
my past chickens had I think 8 nest in a row, but always laid in the same two. I had several hens, maybe 20. I once seen two in the same box, guess they had to lay at the same time. Neat thing was I could be working outside, and could always tell when an egg was layed. It was like a celebration or something, all the chickens would go crazy. People visiting would say something is stiring your chickens, nope, a hen just layed an egg. lol