This is going to be my first winter with my horse. We get pretty bad winters here, meaning that if by chance it doesn't snow, all the grass will die anyway. I am a little worried about maintaining my horse's weight during the winter months. She is a 7 year old, 1400 lb percheron/quarter horse. How much more grain and hay will she have to eat to make up for not being able to eat grass outside all day (For example, will she need twice as much hay as she usually gets and the same amount of grain)? She gets light to moderate riding at least every other day and is currently turned out from about 7 in the morning to eight at night, and the riding will probably not change since I will have access to the indoor arena. I want to make sure that she is getting the proper amount of food to compensate for the lack of grass.