How many days do black hatching eggs?

The -1 4 requires 14-15 days.This kind of bird is distributed in many places, some areas belong to birds, and some are birds.Its breeding period generally starts from April and lasts until July. The birds will make nests on the treetops during the breeding period, and each nest will have about 4-6 eggs.Its eggs will be white and white, with white spots on it, which are generally incubated by female birds.