Watering chickens and ducks without to much mess

I am looking for input on how to keep my coop clean. Basically I wil be keeping 3 cayuga ducks and 2-3 silkie chickens in a 4'x8' coop in my backyard with a run directly underneath the coop. The birds will be freeranged in my 1/3 acre backyard during the day and will only be locked up at night or when we may be away for a day or two. In order to keep the coop as clean as possible for as long as possible I would like to exclude food and water from the inside part of the coop, but dont want to harm my birds. I intend on the birds having access to the bottom/run area 24/7 as it will be predator proof. If I leave open food and water in the outside area of the coop will this be ok at night time? I was considering putting a nipple or cup watering system in the inside area of the coop, but REALLY dont want the ducks to mess up the coop. Also if I elect not to have water up top should I put food up there? All opinions will be appreciated. Thank you all so much.