Brown and/or black fur - with recessive white

Brown and/or black fur with recessive white: No trace of fatty substance color is present in the recessive factor. It is actually a defective factor. What's going on here? Because the bird is unable to convert the parent substance of vitamin A into vitamin A from plant substances containing pro-vitamin A, it is pure white. Vitamin A plays a crucial role in the conversion and formation of fatty acids. This inability also has a small influence on the skin color and to a lesser extent on the horn parts — a consequence of the lack of certain substances in the blood.