Here is an article from Equisearch with some tips on transporting horses during the winter. These tips are great for transporting other animals too, and for hauling trailers during the winter. In icy conditions, it’s especially important to make sure that you’re visible to other vehicles. Make sure that all of your light are working and that decals and slow moving vehicle signs are in good shape. Icy roads also make it more difficult to get moving and to stop. Make sure your tires and brakes are in top shape, and carry tire chains just in case. Finally, make sure that human and animal passengers have enough food, water, and insulation to handle a breakdown.