Yes very good question I have survived two torrential rains and one 3+ inches of snow and of course watched very carefully! The area around the coop and runs is a mud slide - we are all walking around on discarded plywood scrap and tar paper cut-offs otherwise you slide down the hill and land as I did on my backside in the mud! I am also sprinkling pine straw so we can get some traction. In all this wet, the coop and runs stay dry and the mud around it is in part because we are tramping all over and have destroyed the grass. And of course there are no gutters on yet so the drip lines turn into small rivers. I might do a short section of open French drain (not sure that is actually the right word) to get the gutter water out past the runs. Something like an artificial dry creek bed - a trench lined with landscape fabric and then filled with boulders so the water can run off in the right direction out to the wildflower meadow (I think I can make it look attractive and the wildflowers will appreciate the extra water too).