The vet is due out tomorrow to look at my horse's swollen right hind fetlock, unless some more rounds of cold hosing fixes him.
The horse lives out 24/7 and is tough and hardy. There is no lameness. The swelling extends down the pastern and up the cannon bone area. Basically it looks like a fat fetlock. There is a bit more heat in the swollen leg, but not a whole lot. The pulse wasn't throbbing or anything.
I didn't see any evidence of any injury, so maybe he accidentally knocked/bruised himself.