They do somewhat, but it helps to keep it from getting muddy. Plus it cuts down on the smell by helping break down the poop. Really any organic material in the run helps.
check with your city/town to see if you can get free wood chips. I actually just found a site called www.getchipdrop.com that offers woodchips for free from arborists.
Throw any organic material in there (leaves, wood chips, grass clippings, etc) and have the chickens turn it into great soil/compost. I'll often just go into the run and sift some of the material into a bucket, and spread it on the plants. Just try and pick out any fresh poops in it.
I use 1"x1" hardware cloth for the floor of my mobile coop. Works great, poop falls thru no problem. Chickens walk on it just fine, they mainly walk on the roosts. My design is a variation on Justin Rhodes chickshaw, so I'm not reinventing the wheel, many people use it on their floors no problem.
Thanks for the feedback! I agree that there's a lot of folks who drone on forever. Im trying to keep them rather short, informative, and somewhat entertaining.
The past few winters haven't been too snowy, but it still gets plenty cold here. I may close in the sides more for the winter to be...
you can throw pretty much any organic material in the run. There's nothing wrong with plain dirt, but giving them something to dig thru/find bugs is even better. Plus when it decomposes, you can use it as compost.
check with your city/town, you may be able to get woodchips for free. I'm able to get a few loads each year and spread that in the run. Throw some leaves in there too in the fall, chickens love digging thru them.