Can I take my horse out during the winter months when the ground is frozen and slippery?

We make sure there is an area absent of ice before taking the horses out or that the ice will break under their weight. During several days of a winter storm, we tested the paddocks and only two were usable—the others were still solid ice or ice in large areas. I put our horse, Thurben, out first, and I led him out with a chain in his mouth. I walked him around in the field so he would get a feel of what he had to deal with before I let him go. No way would I have just cut him loose after that many days cooped up in a barn, and I did not want to tranquilize him because they get clumsy. If a horse gets to running and falls on this, they can easily break a leg or a hip, pelvis, neck…and they are finished! We left Thurben out for 2 hours because of the wind chill factor. You need to know your horse and whether they will be calm during slippery conditions. A friend of mine drove his tractor in the fields and tried to break up the ice but we had much more ice here, and the tractor could not break through. It only slid on the icy surface so at the risk of the tractor going into the pond, we did not try that.