I tend to leave them unless I am riding first thing the next morning, then I will hose them off, but I put baby oil or olive oil (I am going to try pig oil too) so they are waterproofed!
My two are very heavy in hair, so covered up in pig oil and sulphur and left. When they come in, mud dries and slips off.
If they ever get mud clots on the hair, our field can become a thick clay swamp, I will use a little water and a brush and my fingers on the clumps to break them up but I rarely if ever wash out legs over winter as they take hours to dry.
With my TBs, if the mud was very thick and sticky, I would cold hose and then dry with a towel from knees down as the legs would be dry quicker than waiting for the mud to dry out as our clay takes ages - can still be wet 24 hours later and stuck on.
I leave Belle's legs to dry overnight and brush it off in the morning. She had bad mud fever last year and so far this year (touch wood) we haven't had one sign yet, and the fields have been plenty muddy!
suppose the next question is what works out cheaper. I have bought Pig oil and sulphur at £40 for 10litres. Is it cheaper to buy the sulphur powder and pig oil seperately if so where can you buy it?
Usually I leave them to dry and just brush them off. During the winter, I only wash them before we go hunting or to a show because if you wash your horse's legs regularly it weakens the skin and makes the horse more susceptible to things like cracked heels and mud fever.