How old is the grass and birds that can produce eggs

Grass birds usually mature in about 80 days, but they need to have eggs later.This bird does not have a fixed reproduction period, as long as the climate is suitable to produce eggs.Usually male birds will call for puppets, and then match the females, and they will be prepared to build nests after pairing.Usually 4-6 eggs are produced per nest, and the male and female birds will incubate in turn, and can not be hatched until 13-17 days.