Depends where you live, you definitely want a concrete hard floor with a slight inch or two lift on the bottom so you can hose it out from time to time. If you live in a hotter climate I recommend LOTS of ventilation, if you want to get fancy a mister is a good idea. An outdoor run with dirt is helpful but make sure you have it separated from where they sleep so you can close it off at night for protection. Definitely use a top cover on all the areas they roam, birds of prey love chickens. The sleeping area should have a high roosting bar with solid walls and a roof but make sure it is easy to clean. Make sure the coop has good protection from rain or snow, not so much the outside part but they should have a larger area to dry their feet and feathers to prevent sickness. The laying boxes should be raised and offer individual privacy for each box. Use shavings for cleaner eggs. Make sure if there are cold winters that you have a warm, wind free area for the girls to keep warm. Keep the ease of cleaning in mind for everything and an automatic water is the best thing in the world.