I went into my coop to modify things. I took out the milk crate setup I used as nesting boxes and built a nesting box of wood so that it don't have a top for them to roost on top of. It's about 14" X 15" and next to it is open space about 30"x 20". There's space underneath as well and is high enough that they can walk around under the nesting box, etc. Is one nesting box enough for 3 chickens, assuming they can also use the larger open space next to it as well. I also changed the roost so that it's wider.. about 5.5" wide. Is this too wide? Coop width is 67" and is 73" L. Run is 4ft 9" W X 10ft L x 4ft 2"H with no roof/cover << They're locked in coop at night.. as well as if we're not home. Is this adequate for 3 full grown standards? How many can this setup hold if I wish to add more?