Base of chicken run?

Are you roofing this run?

A lot of people like sand- we have natural sandy loam and it's very good, plus you can always add pavers or something similar for wet weather.

With a small number of hens, you'd be better with a smallish run and roof it...and deep litter is not good where it can get wet- you get an awful mess.

Not sure where you live or your predator issues, but most of us run a barrier underground at the edges or, in a small setup, floor the run with 1/2" gauge hardware cloth and cover with sand.

 

Even a run with a roof will get wet. Water/snow will just blow in. But it's substantially better than if there was no roof at all.

A muddy run will smell. Badly.

I use sand in my run. Love it. Granted, my run is not "muddy" -- but whatever water DOES manage to get in seems to go away really quickly.

IMO, any woody product (like chips, sawdust, straw, whatever) will get moldy and need to be changed out pretty frequently. I suppose it depends on how much work you want to do.

 

Good for you for giving them the extra space!
You will probably want to build up the sides with timbers or 2 by material. I use wood chip as a base for my run, and am very happy with it, but my soil drains quite well. If your soil doesn't drain, building it up and adding sand is probably your best bet. I would definitely not use shavings or straw--makes a mucky awful mess!

 

If you don't mind a bit of exercise, the best thing would be to buy a small dumpload of roadbase or other mixed gravel-sand aggregate. Either use that alone, if it is appropriate quality, or put in a bunch to raise the run well up out of the mud and then top with sand (which will gradually disappear but then you can decide whether to repeat it or what).

One warning: sand or gravel or roadbase dumped onto already-muddy ground will not last nearly as long as if you wait to apply it til the ground is well DRY. Dumped onto mud, it will mysteriously vanish into the mud over a period of weeks or months or a year, and then it'll be as if it had never existed. Whereas a good thickness of roadbase or whatever applied to DRY ground will last nearly forever.

So, you can either add roadbase or whatever now (if you can get a wheelbarrow in there!) and just figure on needing more some time in the future; or you could try a short-term solution and wait til summer to add roadbase. In terms of short-term solutions, your best bet would be coarse woodchips, as they will not hold moisture as badly as finer chippings or shavings or straw, nor will they decompose into water-holding humus (=mud!) as quickly. You may or may not have to rake them out of the run at some point in the future, if they threaten to decompose into muddier stuff. Alternatively, if the area is only a *little* muddy, you could potentially put a few pallets in there for the birds to use during muddier weather and figure the ground will be firm enough to bear their activities most of the time. Depends on how bad the spot is.

The other thing well-worth doing is to figure out how to make the area less muddy. Trenching around it, to lead the water elsewhere downhill, can be very worthwhile. And make sure there are gutters with appropriately-directed downspouts on any buildings that may be contributing roof water to the area - you can use nonperf black corrugated drainage pipe to make an 'elephant trunk' thingie to lead water well away from the downspout area.

Good luck, have fun,

Pat