1. Beta-carotene that is not converted into vit A serves a protective barrier against disease. 3. VITAMIN A DEFICIENCY Vitamin A utilized in the body is dependent on 1. Quantity stored in liver a. Deficiency symptoms appear in 1-2 years due to high amounts stored in liver 2.
Wild Lifespan. In their natural wild habitats, cockatiels, on average, live between 10 and 14 years, indicates Animal Diversity Web via the University of Michigan. Their average age for passing away is younger in the wild than it is in captivity. Captive Lifespan Cockatiels that are kept as pets -- or that live in other captive settings -- can stay alive for up to 25 years or so.
Quick Answer. Common indicators of a cockatiel's age include appearance of the eyes, appearance of the feathers and behavior. While a cockatiel can live to be 15 to 25 years in age, most physical changes occur during the first year or two, making it easier to identify younger birds and more difficult to determine the age of older birds.