how many feet of coop should they have (indoor/outdoor)
Generally figure they ought to have
at least 10 sq ft per chicken of indoor+outdoor combined. A lot of people would do something like a 4 sq ft per chicken indoors, plus a run at least 6 square ft per chicken. More is pretty much always better -- reduces likelihood of them starting to peck each other to pieces, and potentially leaves room for more chickens in the future, unless your town laws restrict you to just 3 chickens or something like that, in which case that is prolly not an issue.
The only thing that can be said against 'larger is better' is that if you live in an area with very cold winters, a small coop is easier for the chickens to keep warm with their own body heat. OTOH a smaller area can be sectioned off *within* a larger coop, to allow them to stay warmer, so larger probably always *is* better even in cold regions.
You *could* just build a coop, no run, and let them free range in your yard most of the day every day. HOWEVER this may pose a problem in severe winter areas, plus they will create dustbathing potholes all across your lawn and scratch your flowerbeds or veg garden to bits and eat your plants and poop all over your patio, and fly over your fence to annoy the neighbors. And in most places, periodically get eaten by a wide variety of predators. This is not an argument against free ranging, really -- but you want to think about whether these tradeoffs are what you want. Many people compromise by letting them free range only a little, under supervision... and for that, you are back to needing a run for them the rest of the time.
How many should I get too
I have 1/2 an acre but my town allows it.
Depends how big a run and coop you want to build, and how many chickens you want
Almost everyone here ends up wanting to get more chickens than they started with -- this is a baaaaaad place to hang out if you are trying to restrain yourself LOL -- so there is probably a WHOLE LOT to be said for getting fewer chickens now than you ultimately think you might want, to allow room for more later on. That said, it is better not to be constantly adding to the flock and upsetting the social order.
Hope this helps,
Pat