Those tiny teeth dog combs! They’re for fleas or lice but I used it to pull sap and mud (and dried soggy poops) out of winter hair.
Great mud you have going on! Rivals the New York mud! I agree not ideal but there’s really nothing you can do about it unless someone has a gorgeous mud free facility. We have mud under all of the gates right now, just fortunate my guys don’t like to hang out and wade in it. They’ll have a good roll in it though.