My 3 year old thoroughbred is 16.2 hands and 850 pounds. She is still growing and has lots of filling out to do, she has been dewormed. I am looking for info. on feeding her to help her gain weight. Also, any suggestions on how much a horse this size should weigh? I currently have her on trimax, she has been worked up to 4 pounds a day now (divided in 2 doses), free choice, good quality hay, salt and mineral blocks, and water. Not sure how long I should wait to see the weight gain, any supplements I should add, or how high up in the grain I should go. She is currently just out to pasture resting her young bones and learning how to be a horse (I bought her off the track). Any suggestions would be appreciated.