Limestone grit offers similar properties to oyster shells. At 38% calcium, it is a viable alternative, and assists in developing a healthier crop. It is partially soluble and will break down in the gizzard. Important during the early stages of life cycle to support skeletal systems. Grit # 1 & 2 is used for poultry and smaller gamebirds, ducks or waterfowl.
Limestone is the most common source of calcium used in livestock feeding. The shell of each egg that hens are laying is made up of nearly 95% calcium carbonate by dry weight. To produce hard eggs, chickens will be consuming up 20 times the amount of calcium in one year than the amount of calcium that is contained in their actual bones.
Magnesium also plays a very important role in poultry feed and hence limestone should contain minimal magnesium. Texlime manufactures limestone grits and limestone powder that is high in Calcium (>38%) and very low in Magnesium (Mg <0.4%) that can be efficiently used as Poultry Feed.