How to tell whether budgerigar is healthy?

The head feather and back feather of budgerigar are generally yellow with black stripes, with more wing lines, and the coat color and stripes are like tiger skin, so it is called budgerigar. Budgerigar is a small species of Nautilus, with bright feathers, lively temperament, crisp calls, innocent and lovely, and easy to domesticate. It is one of the most popular birds in China. The head is round, the beak is hooked, and there is a wax film above the beak (the sex of most budgerigars can be distinguished by the color of the wax film). The budgerigar has short legs and four toes. The second toe is forward and the first toe is backward, which makes it easy to climb trees and objects.

This bird is yellow-green; The feathers on the back of the head, neck, upper back and wings are light brown, and each feather is yellow and black; The throat and face are yellow; There are different degrees of blue-purple under the cheeks and three black spots in the throat; Chest feathers have narrow black edges. The main flight feathers are light blue; The flight feathers are grayish green with light stripes; It is gray with white stripes inside; The feather in the center above the tail is blue-green, the tip is black and the inside is black. The beak is olive yellow and the wax film is blue; The iris is white. The wax film of female birds is grayish brown or flesh-colored, with only a little light blue, which will turn dark brown during the breeding season. Chickens are dark, and the wax film of both male and female chicks is pink. It takes 3 to 4 months to grow into a bird-like feather color.

The average life span of budgerigar is 7 years. It is16 ~18cm long and weighs 35g. Yellow forehead and face. There are purple-blue spots on the cheeks. The upper body is densely covered with yellow and black pinstripes. The waist and lower body are green. There are small black spots on the throat. The tail feathers are green and blue. The iris is white. The mouth is gray. The feet are gray and blue. The male bird's nose bag is light blue, and the female bird is flesh-colored. ?