Ok, I know it sounds so silly, and not ilness related...
But I wasn't used to see my horse's penis. He just didn't seem to put it out much. I was never worried, my horse is healthy and if he wanted his thing inside, who was I to complain. When he was very relaxed, the tip showed, but never more than that.
So in the last days I see that when he relaxes, he puts the whole thing out. Fully, nicely relaxed. I find it weird, since he never did that in the years I had him.
The only thing that changed recently was a thorough cleaning and bean removing (I always tried to keep it clean, but just recently I found out a way to do it properly)
Might this be related to this sudden "hanging stuff"? I wonder if the bean /or the deep dirtiness bothered him to the point that he didn't like to put it out?