My best advice for the coop and run set of fowlers is to simulate the forest floor in your coop and run to improve the overworked soils there. Deep litter in both areas that has areas that are dry(as in under trees~can be done with tarping over a portion of the run), combined with open areas that are exposed to the sun and rain, layering of organic, carbonaceous materials in both places~coop and run~so that the nitrogen of their droppings is "eaten" as it composts.
In essence, you will have your chickens living on an ongoing
compost pile that works much like the floor of a tropical forest. The beneficial bugs, worms and bacterias will inhibit the overgrowth of the less beneficial and more harmful pests and organisms that would otherwise live in barren, wet, contaminated soils of the typical chicken run/yard. Leave no area of soils bare and have at least 6-10 in. of organic "pack" underfoot. Provide good drainage, with no standing
water, by keeping the pack of litter leveled off in all spaces. You can add twigs, half rotten chunks of
wood, leaves, fibrous weeds,
lawn clippings, wood shavings, etc.
The chickens will work the material from the dry side to the wet side and back, keeping it aerated...you can aid in that by tossing BOSS into areas that are forming moisture "caps"~areas of litter that are stuck together and molding~and let the chickens have a ball. Eventually the bottom layer of this litter pack will be just like well composted, rich soil...you can take some of this out now and again and use it on the garden but you don't ever want to remove it all or be tempted to "clean it out". The litter is well inoculated with all the wonderful nematodes that will keep it working and healthy and you don't want to lose that valuable soil culture by starting all over again from the beginning.
You can lace the whole thing with sweet lime or
wood ash now and again to sweeten it up, lower the acidity and provide the correct pH for the organic life you are trying to support in that soil.
Your job will be to regulate it all, assessing the correct moisture content by feeling it...if it clumps when you squeeze it and stays clumped, it is too moist. If it won't clump at all, it is too dry...you can add more moist materials at that point like grasses,
hay, etc. If too moist, add
dryer content like wood chips, shavings, dry leaves, etc. If it smells bad, it needs aeration and more ventilation, more dry materials.
Soon you will be able to dig to the base and see good bug life living there and the soil underneath will be soft, spongy and will have an earthy smell...not one smell of chicken in sight. That kind of soil will cleanse itself, renew itself and will be able to filter the high levels of nitrogen down to the worm life below that feeds on those nutrients.
That's my $.02....many are using it and finding it worthy of being called a healthy alternative to rotating space that you simply do not have.
ETA: Don't forget to reserve one dry area and create a box full of fine clay, sand, soil for dusting. That dusting is one of the best ways to keep your flock free of external parasites...they need it and will self maintain if you only will provide it. The box
should be deep and wide/long
enough for several hens to dust at once...they enjoy this social time and grooming time together and it is an important aspect of their self sustaining health care. Some people use a baby's wading/swimming pool to contain the materials and they can be obtained easily or cheaply enough in most areas.