In Countryside mag a lady had an interesting solution to that problem. She put all her weeds, garden clean outs (corn stalks, bean vines, squash vines, etc.) in the run and just kept adding material of this type. She said the birds had great fun scratching through it, it kept the run drier, and the bugs love to hide there...giving the hens more to do. She said she kept this up all year and at any given time her hens were standing on at least a foot of leaves, dried grass clippings, and garden roughage...even into the winter. This sounds like a wonderful way to make some compost!
My hens mostly freerange, but I am putting in my garden, so they must be in the "big house" until the plants get some size on them. This is the first time they've been locked up and they HATE it! My run is approx. 65 ft. x 10 ft., with a shade tree on one end and a couple of dusting spots.
I found an interesting thing about free ranging in my yard...the dogs eat the poops!!! Yucky but it keeps me from stepping barefooted in a mess!