From Eleanor Kellon, VMD, staff veterinary specialist for Uckele Health & Nutrition.
(1) Avoid rapid changes in diet. Take 5-7 days changing from grass to hay
(2) Provide 10 gallons of water daily.(suggestions below)
(3) Turnout unless weather very severe. Inactivity is a risk factor. Place water and hay close together as horses usually drink water soon after eating hay. Warm water is consumed more readily. Do not allow water to freeze over. To encourage drinking water, add at least 1 ounce of salt to the feed every day. (or dissolve salt & spray on hay) Add warm water to pellets, hay cubes and sweet feeds. Beet pulp is ideal as it can hold 4 times its weight in water. Wheat Bran improves appeal.