I'm getting four runner ducks this weekend, which came as a complete surprise to me. Someone where I get my feed from wanted to get rid of them and asked if I wanted them. I was going to wait till next spring, but the price was right and I couldn't pass them up. Anyways, I need to make them a pen and I'm wondering what the square footage requirement is for runs for ducks? I have two old dog houses that I can use, but I need to know how big to make the pen. Thanks!