Yeah guess the OP needs to clarify. I personally wouldn't out more than one chicken per 20 SF simply because of the maintenance and cleanliness. I think the 8-10 SF assumes regular cleanings.
16x8 is plenty of room for 4 hens + a Roo... unless I am readying their post wrong.
The widely accepted rule of thumb is 8-10 SF per chicken in a run. So in theory they could have up to 16 chickens in there.
I'm probably not a good one to comment though because my chickens have 363 SF per...