Can budgerigars open their nests for ventilation after their parents hatch their young? It's very hot now

Yes, budgerigars can open the nest box for ventilation after the parent birds hatch. But be careful not to scare the young birds, so as not to cause nesting. At the same time, keep the temperature and humidity in the nest box, especially in hot weather, to avoid the discomfort of young birds due to high temperature.