All this spring rain makes for a muddy, horrible chicken pen, don't you find? I tipped stored autumn leaves and plenty of weeds into my fenced run over the weekend to cover the soil and give the hens something to scratch and forage in. They were very grateful.
There's a great article by Janet Luke here on keeping a healthy chicken run. She angles it towards keeping the run smell-free, but the principle of chucking in lots of organic matter applies just as much to keeping it mud-free.