to the OP: your run around area outside the covered part makes for a perfectly ample chicken coop. I agree with this guy's idea about perches, they roost at night, keeps them safe from predators.
I strenuously disagree with the bolded bit however.
Use hay, not straw, keep it clean and refresh it now and again, you don't want mites making a home there, they can bite a chicken crazy. You definitely should have hay anyway - if you strew it around it will catch poos, they will scratch through it for seeds creating the most wonderful basis for compost known to man.
The same applies to what we call sawdust over here - a kind of wood shaving you get from the sawmill. six inches of dry sawdust in the coop makes life so much easier. Turn it over when it gets a bit smelly, and shovel out under the perches every few months & replace. My stars, you put that in a black polythene bag with a few holes in it in the sun and rain for a year and you have black gold.
Pure black gold.
keep their water fresh. It's a little known fact that chickens cannot drink warm water, so be sure to have it somewhere cool and keep it clean and fresh.
I hear tell that if you have a guinea pig in the run you will not get rats. it appears the rodents fight it out and the bigger one wins the territory. We had a hedgehog which I believe is not native in the US?
In closing the guy I quote is dead right about a happy chicken being a full chicken. I provide chicken feed. Chickens do not overeat, interesting but true. The only problem you might have with chicken food is other birds getting to it. I always feed at night, it gets them back in the coop.