What's wrong with the yellow bird tail hair?

The yellow sparrow tail hair was lost because it was in the feather change period, and soon it would be new.This bird usually changes hair in autumn, and then uses new feathers to survive the winter.When it fades, it does not need to be replaced, but when you have new hair, you can feed a little nutritious food.At the same time, pay attention to cleaning and keeping clean and tidy in the cage, which can also reduce the possibility of birds' disease.