The ducks are outside all day, every day except in winter when everything is snow covered. So the run handles a dozen chickens 3 seasons and everyone during the winter. At 225 sq ft, I could have up to 20+ chickens based on 10 sq ft per bird. The funny part is how I separate the ducks and chickens so I can let the ducks out, and keep the chickens in. I open the coop door (inside the shed) and the chickens all rush out into the shed for treats that I have piut on the floor. The ducks wait patiently until the chickens are out of the coop (into the shed), and then I open the pop door, and all the ducks rush out into the run. Then I close the pop door, and toss treats into the coop and open the coop door, and all of the chickens rush back into the coop, then I go outside and open the outisde pen door, and all the ducks come running out to play in the pool. Close the pen door, and open the pop door, and the chickens are out in the pen. At night, I just open the pen door an hour before dusk, and the chickens get to free range for an hour, and everyone goes in as the sun disappears. I have rope lighting along the rafters in the pen, and this provides light which seems to calm the ducks. They don't like to go inside a dark pen or coop, and will huddle outside the doorway until one has the courage to go in, and then they all rush in!
I highly recommend getting ducks. They have a lot of personality, they are sort of the goof balls of the bird kingdom. Since mine are mallards, they are fully flight capable, and we really enjoy watching them take their daily flights. They fly around for 10-15 minutes, going in large circles about 1/2 mile around the house. Then they all come in for a landing, which can be very comical as well.