I had to put boards down in my coop when the snow started to melt because my hens were ankle deep in mud. But I didn't get them picked up soon enough and now there is mold (white fluffy kind) growing under them!!!! How do I safely get rid of it? They can't get to it now because it's under the boards. Their run is dirt and is just fine so should I lock them out of the coop for a while or what?