Years ago my sister was riding our horse back home from some friend's house and decided to ride across a lot on which a new house was being constructed. She ran across one of these mud holes and the horse sank in up to its belly. My sister jumped off, but the horse was stuck. She came home pretty upset, and we all rushed up to see what we could do. We called our vet to see what he could suggest. He came out and found the horse to be ok but quite stuck. He suggested we call a tow truck. We did. They managed to get a strap around the horse's belly somehow and winched it out of the mud. As soon as he got onto firm ground the horse got on its feet and calmly walked home none the worse for wear.