8 should be the min and if they are soft feathered large they should be down near the ground but the rest of breeds would be fine to get up high my isa brown can get 2 and a half meters of the ground rather than my Plymouth rock can only get half a meter so just depends
I have 4 nesting boxes for 54 hens. Probably not enough, but they don't complain. They line up and wait. Sometimes 2 hens will be laying in the same box together.
The best height is 24 inches from the floor, but there are no hard fast rules. Make sure your roosts are higher than the nests, and the nests high enough to clean under them. IMHO, figure on 1 box per 4 - 5 hens.
Sorry to butt in, but why 24 inches high for nests? If you do that, then the roosts have to be 3 feet high? That would leave only inches for my hens to roost, hehe. I was thinking 1 foot and 2 feet for the nests and roosts respectively...
I have an Americana that has decided to share with the sheep I fill the feeders with hay and before I know it that silly hen is hopped up into the feeder and settling in. The sheep just keep eating and she must slowly slip down. There is nice nest by afternoon in the feeder with a colored egg in it. I have have 3 boxes in the hen house and only one gets used. They wait their turn. The other favorite spot is the empty brooder. soft floor of shavings and not in use. There are 4 hens that lay in it daily.
We are currently looking at others designs for a bank of boxes. I like the pictures of the two rows of 4 storage boxes. That appears clean and simple.