I need to build a couple breeding pens for some new chickens that I would like to breed as purebreds, as opposed to my free-range mixed flock. I was thinking of an 8' x 8' pen divided in 2 so I could keep one breed on each side. But a small portion of each of those would have to be for 'indoor' shelter since I have to space to make a chicken house for these pens. Is a 4' x 8' space enough for say 4 chickens? Would I need to use bedding in there? Or is bare floor fine and on a related note, if I let them out to free range would they return to their respective pens at night the way my mixed flock returns to their coop?