You will probably have about 1-2 wheelbarrows full of manure/month. I own 40 chickens right now. Chickens and rabbits produce the most valuable manure. I moved to the country to have my horses in the back yard, and the chickens came later. So, my manure handling is from what you do with horse stall soiled bedding--you pile that up to kill parasites and start it degrading from the heat. Therefore, I just pile manure from both together, then let nature break it down for at least 4 months before the planting season starts and I can till it into my gardens.
You should be on BackYardChickens.com--a sister site--and study up. Mostly, the best chicken bedding is pine shavings. Pine shavings in a pile take a full 5 years to break down on their on. BUT, you could use a rake and try to separate the manure from the bedding.
If you haven't owned chickens before, I can tell you that an unkept coop hits you with a wall of...filth. NOTHING is worse, even a dirty kennel is less offensive. (NOT my personal experience with my birds, but I've smelled it before!) Most people like to use the deep litter method, where you put down ~4 (3 cubic foot size) shavings in the start of the winter, then rake it often to get the poo that is old, and dried, to fall to the bottom. Then, you strip the bottom of the coop in the Spring and use it for gardening and for mulching (the shavings.)
I've owned chickens for about 6 years now, and I started with one hen. You're really taking the plunge. My 15 (5-9 month old) young hens are producing 9-13 eggs/day. Watch the Cornish X. You MUST remove their food for 1/2 of every day, or they will overeat and can break their legs. I replace my layers every year, now, and I butcher all hatched roosters and my old hens. They meat is outstanding, large roosters produce a LOT of meat, even though they are meat birds, and I can always fill their food and water, and leave it "free choice." Just some thoughts. Some folks cannot get enough of their Cornish X's, but they aren't always the easiest to care for.
I currently have 6 butchered/dressed/frozen birds, waiting for my next chicken dinner. YUMM!!