I know what you mean about the muddy runs. Yuk. Mine get that way. I hate it, and it worries me about their feet. But so far no problems, but I think that's because they do dry fast once the rain stops. Your's sounds like it stays muddy longer. You don't have the underlying rock.
Does the horses get enough hay to have all thru the night? I know they don't need it, but it might keep other habits from developing....LOL....kind of six of one and half dozen of another huh:\
Becky
Yes, fewer problems when we give them ~plenty~ of hay. And we do. The night Cyn had cribbed, I think she got shorted. She was pounding out there, and we went out, her hay was gone, she had played with her feeder, and chewed the board right next to it. I think that's all it was. We gave her some more hay.