For standard size breeds, I've found these specifications to work well for roost bars in the coop:
* At least 1 linear foot of roost space per bird
* Roosts at least 15-18 inches from walls (to reduce poo on walls)
* Roosts at same height or everyone fights to use the highest roost bar
* Roosts 20-24 inches apart so chickens cannot reach over to pick on each other
* Roost bars no higher than 2 to 2 1/2 feet off the coop floor to reduce foot/leg stress when birds jump down off the roost
* Roost bars no closer to the coop ceiling than 2 feet to reduce moisture collection (and frostbite) on combs and wattles during winter
* Roost bars in discrete, separate areas of the coop so birds can space themselves to reduce stress. Multiple, spaced roost bars have worked much better than 1 continuous roost bar, especially for a flock with roosters, laying hens, and juveniles.
* Roost bars of untreated, unpainted pine 2 x 4's with either flat or narrow side up
* Roost bars (2x4's) sanded on all 4 edges for foot comfort
* Roost bars inserted into fence post brackets so they can easily be removed for cleaning (fence post brackets are about 69 cents apiece at Lowes or Home Depot)
* Roost bars higher than nest boxes, so they're less tempted to roost on or in nest boxes
* Roost bars positioned away from feeding, watering and nesting areas of the coop so chicken poo does not drop into these areas.
I don't have roost bars in the runs, so I can't help you on that one.