Just curious if I need to add anything to the floor of our run. Its mainly gravel as you can see and has a bit of grass here and there. Its not covered, and we live in WA state where rain is abundant. Will the poo decompose easily on this surface or should I add anything to aid decomposition? Also should I consider a tarp over the run area due to rain?? Its a pretty big run and im not sure I could cover it all with a tarp. I dont want any smell and want to keep it as sanitary for our hens as possible and keep the neighbors happy with a fresh smell.