What's wrong with gray swallows?

Gray swallows may not be mature or less than the breeding season.If you want to breed, you must first be in estrus. When you find the right partner, you will be paired and prepare to build a nest.After the nest is built, the female birds will start laying their eggs. A nest will produce 4-7 eggs, and then after 13 days of incubation, the chicks can break out of the shell.Birds will feed the young birds until its feathers are full and leave the nest.