I have 2 pekin ducks, Paisley and Paxton, and they are about 4 weeks old. I am worried because I think they might be laying down in their poop and bedding. I'm 99% certain that this is the cause. It gives them a brown belly. I tried washing it off with just water but it doesn't work. Does anybody know of any way I can wash the brown spot off their belly without getting them sick? I figure I can't use soap but I don't know what to do.