I really struggled to keep my rugs dry during the wet weather. Hanging them up in and around the stables didn't make much difference as they were still cold and damp the next morning, I know that some people leave them on their horses but I didn't want to leave my horse in a wet rug all night...
Wow that is disgusting, I would leave straight away and make it perfectly clear to the owner why I was leaving. Have you discussed with other people at the yard? They should be made aware.