Coop/Roost space Dilemma!

[Mr Bojangles]

So I'm renting a cabin that had a chicken "coop/pen" on it. So I got some chickens. Just a pain fenced in 12'x16'.added a roof. Added nesting boxes. Added the roost. Now that winter is coming I need to shield them from the elements I guess. So I found a box. It's 10'L x 24"H x 12"D. I think it's too small. Found another identical box I could join to make it 24"D. Pics of my plan and what I currently have are below. What do you think? I want help them but is this too small? I have 16 chickens. Should I block the off the entry doors at night? Add some vents? Any ideas / suggestions would be appreciated

 

[Mr Bojangles]

 

[Mr Bojangles]

 

[Folly's place]

How about plastic sheeting or tarps on the walls, up to 6" or so from the roof? Wind protection and ventilation. Mary

 

[Mr Bojangles]

Alright! The old pic and design are above. This is how it came out! I've decided no ladders to the roost so far. I don't think they need them even tho everybody says I do. I think the perch is good enough. Maybe later

 

[Mr Bojangles]