So I'm cleaning out my run. I noticed a while back that the dirt had a weird hollow sound when I walked on it, so I dug up a little of it. It comes up in huge 1" thick slaps of poop and under it is the leaves I put in last fall, it's all wet under and STINKS like the sewer. Right now I'm digging out all the poop layers and figure I should let it dry before putting down fresh dirt, but is there something I can do to keep this from happening?
Keep your ground turned up. The smell is most likely trapped methane from the rotting vegetation. The hardened layers prevented proper airflow and didn't allow for aerobic bacteria to do their work and break down the leaves into compost. Unfortunately, it's going to stink like that for a while, even after it dries out. I used lime to get rid of the stench when that happened to me, but I also didn't let the chickens anywhere near it for a couple weeks after. I heard DE sprinkled in sometimes prevents that caking/stinking mess. I have never tried it, so I can't say for sure.
The leaves have gone anaerobic and are bound to stink. The gasses given off can even be toxic. Once you stir things up the smell will be back to normal as it gets oxygen and starts to dry out. Not much you can do to keep it from happening short of taking a pitch form to the run from time to time to break the soil up and turn it a bit.
I agree with the sand. Also, if you put down a temporary layer of pine shavings for a day, that will immediately make it smell a little bit better. Then, you can rake that up and compost it. That's why horse--people love pine shavings--they make the barn smell nice!
