I'm just about to do soemthing with my hen run too - used to be grass, now a sea of mud. My son and I are going to level it off, lay terram (weed fabric) then put down gravel (the cheapest I could find is 20ml at a local builders merchant for £45 a ton including delivery!) There will be a run off channel down the side of a wee wall that runs the length of the run, so I'll be able to hose it down every now and then