A few days ago one of our horses began showing some signs of diarrhea. At first we thought she might be colicky since her poop had a disturbing quantity of dirt in it. We have elevated her hay so it is no longer on the ground where she can ingest the dirt with her feed. It has progressed to mild lethargy and a runny nose since then. My research has informed me that it is most likely just a cold she caught after the last heavy rain storm we had, since she has not presented with any further symptoms. Is there anything I can do to make things a bit easier for her while the cold runs its course?