Okay, I am sick to death of the soggy mosquito-breeding marshland my duck pens become in the summer. I've been using a deep-litter method for their night pens, then they free range during the day. But I'm ready to install some drainage under the night pens. I've heard of folks doing gravel with sand over the top, and I have access to some inexpensive sand by the truckload... Can I just do the sand and skip the gravel? Or is there an issue with that? Also, how deep do I need to dig? How do you keep predators out (with the deep litter, there is wire under the pens that the bedding goes over)? Should I install some sort of french drains or similar under the gravel? What would happen if I just installed the gravel/sand over the wire at a raised level? I guess I'd need to put in retaining wall or something, right? What are you doing for drainage in your pens? All input welcome!