Greeley calls chickens "pets" and will allow them with no cap on numbers. However, roosters are not allowed. Also, even hens can fall under nuisance laws, so as long as you keep it clean, you're fine.
Evans allows roosters, technically, but you are limited to 4 pets overall, cats, dogs, and poultry.
Always good to glean ideas to save on food costs and provide variety for our gals! My thoughts? Most have been said, hardware cloth frame over some grass or seeds to provide a mini pasture in the run, chicken wire / stake compost and seed filled cylinders (think tomato cages) to allow for more...