Calcium is an essential component for healthy bones, feathers, etc. Without Calcium & vitamin D3, birds cannot maximally utilized by the body. Natural sunlight will allow the body to produce normal amounts of this vitamin. .Avian lighting can also perform this function with your birds indoors. It is important to use vitamins made for birds.
The Bridcare Company Calciboost Liquid contains vitamin D3 required for your bird to function.