Thanks a lot everybody. I am living in Pakistan and those 2x2 brick houses/enclosures are common here that's why I mentioned. As for my design of coop I made it between two adjacent walls (between house boundary wall and the building.So have two sides closed (wall ) and the other two open (metal wire net) Roof is net+Tarpaulin+metal sheet on top to waterproof. Cold winds do cross the coop in this design. The chicken sleep on top of a wooden crate having a small crate put over the main crate (to one side) to block wind from one side.
I also have 6 chicks (1.5 months old in a separate coop (open on all sides but put under my car shed. I put a plastic bucket sideways for them to get cosy but they prefer to sleep on top on it all cuddled together.
The breeds are both local non-descript as well has locals crossed with White Leg Horn.But my friend always seals his coops from all sides with tarpaulin which I based on your comments feel is unnecessary.
I dont provide them any commercial feed ( I kept chicken to avoid these feeds) put them on wheat, millets, greens , sunflower seed, fruit peals etc.