We were at a mans house who keeps his in his finished basement. He used plastic piping to make his pens with a netting between the top and bottom pipes to keep them in. He had 2 adult pens and two baby pens. He has a room just for the chickens (silkies). It was the neatest set up. There was absolutely no smell from them. Made me want to turn my basement into a chicken house. Maybe one day.