Weaning will take place a few weeks after they fledge but the chicks will not be fully independent for another few weeks. By now they will be eating on their own and soon will go through their first molt. After their first molt the sexes will be very apparent. Males will start showing the traditional male colors as the beak turns red and the females beak will turn orange. By six months of age, both sexes will be ready for breeding.
Males do mature earlier than females but breeding young males is sometimes problematic.
Young males may toss eggs or chicks from the nest in their excitement. If a young female begins breeding too young, she can become eggbound and die. After the chicks are raised and on their own, the parent birds may try to start the whole process over again right away. Some Zebra Finches will continue breeding as long as you will allow it as it is their instinct to do. The caregiver must intervene to force them to rest.