How many days do you need to hatch eggs

The blue song is 13-15 days.This bird is mainly distributed in Asia, and many places in my country are distributed, which is also its place of living.It generally breeds in woods above 800 meters above sea level. It will make a cry when breeding, and it will start to make a nest after pairing.Usually, the nest is done by the female bird. The next day after doing it, it will lay eggs. One day can be produced, and a total of five or six pieces will be produced at a time.