Oh, good decision! My biggest regret is not having built a walk-in coop. I began with a 4' x 4' coop for two hens, thinking that would be all I'd ever need. I caught "Chicken math" (the obsessive need for more chickens), and the 4' x 4' was soon housing five chickens. They had a small outside run, but it was also not a stand-up affair.
Having limited budget, I just jerry-rigged and added on over the years until it got to be such an untenable torture (for the human) chamber, I finally built a proper run several years ago. Chickens and humans spend most of the time out in the run during the day, so it's very important to get that exactly right. Breaking the run up into partitioned space really helps in keeping a flock happy by creating interesting space for those who wish to get away from individuals they detest, and an enclosure called "chicken jail" where a naughty troublemaker can be kept separate while still being part of the flock. I have a young sex-obsessed cockerel in jail right now to maintain the peace.
This is my covered run with a coop situated on each end of it. The side covers come off in summer for maximum air flow. In winter they create a greenhouse effect and it makes it very comfortable on below freezing winter days. The substrate is sand so the poop is scooped daily, keeping it odor-free.
If you click on my user name, then click on "profile page" then click "albums", you will see one titles "new run". There are all sorts of photos of the construction.