I have a five year old horse that over night developed a swollen fetlock. or at least the swelling seems to be in that area, it looks more on the inside of his leg then the outside as well. it isn't hot, I don't see any cuts. he won't put his weight on it, but doesn't appear to care at all when i poke and prod at it. the day before I was working on his trailer training, and he may have kicked at the door, also, that morning before I was around him apparently there was a scuffle at the feed bin, that I was wondering if he slipped or something. any ideas?