Description Dr. Thornleyâs Hay Balancer G is a premium vitamin and mineral supplement for horses on a grass hay diet. It balances macro-minerals such as calcium and phosphorous, provides critical trace minerals, improves the protein profile of hay by providing critical essential amino acids, and includes stable yeast cultures and important vitamins to support digestion and gut health.Dr. Thornleyâs Hay Balancer comes in two sizes: 20 lbs in a resealable vinyl bag or 60 lbs in a paper / polywoven bag.One 20 lbs bag contains:A 30-day supply for an adult horseA 15-day supply for a pregnant/lactating broodmare or growing weanling.Measuring scoop included in each bag.Intended to be used as the only supplement to a grass hay ration.