What's wrong with the tail hair?

The tail hair was lost because it was in the feather change period.This kind of bird will change twice a year. The first time is spring, the wedding feather is changed, only a part, the second is summer, and all the hair will be replaced.Pay attention to keeping environmental hygiene during the hair change period, clean up the feathers and feces in the cage, so as not to get sick.In addition, it is necessary to feed it some highly nutritious food to promote the growth of new feathers.