You've come to the right place to find all sorts of suggestions!
First, I will agree with Jackson - find out what works well in your ecosystem. Here on permies, giving us your grow zone, your typical highs and lows, and general storm patterns, will help us give ideas that are applicable. That applies to breed of chicken too. There are some breeds I'd never raise on my Wet Coast Farm, that I *know* are recommended to people who face very cold temperatures (which we don't get.)
Second, I can't recommend enough that nest boxes and perches be removable for cleaning. It's a lot easier to give them a really good scrub if you can tip them this way and that, and then dry them in the sun to disinfect them. Definitely think cleaning while designing.
Third, you may have never seen _____ (insert predator name) on your farm before, but get chickens and they'll show up to check out how easy it is to break in. I'd never seen an owl, but when a friend of a friend gave us some starter chickens, the owl showed up the very next day. So please research local critters that are attracted to chickens, and build to protect your birds.
Forth, rats and mice will absolutely show up and get into any feed that's not protected. I hang my chicken feeders above my perches to make it harder - simple, cheap and amazingly effective. Extra feed is in a closed bucket inside a garbage can.
Fifth, quality housing is expensive. We no longer by "chicken wire". 1/2" Hardware cloth (the welded square stuff - different names in different ecosystems) will keep many more wild creatures out, but it's much more expensive. It's cheaper by the 50 Ft roll, and it takes a far amount if you find you need multiple secure runs. I am a great fan of upcycling, but only if the results will be safe.
Sixth, have a back-up plan for emergencies. People give us dog crates they no longer need, and they can be used to quarantine a sick or new bird for short periods, but not for very long. I try to always have at least a 4'x4' secure cube in case an injured bird needs recovery time.
Lastly, enjoy the journey. "Chicken TV" is a thing... For many permies, Chickens are "pets with benefits". They get you fresh air, exercise, and entertainment. They eat your weeds and bugs. And they give you awesome eggs and useful manure. Often they don't save you money, because Industrial eggs from chickens in huge barns are too cheap, but on a nutritional level, bug and weed eating chickens lay healthier eggs.
