What's wrong with the crow does not reproduce

There is a certain difficulty in the artificial reproduction of the crow. It needs to simulate the environment in the wild, so that it will be paired with the nests.This bird has a nest in the nest in the coniferous forest or coniferous broad -leaved mixed forest, and it will have eggs after building the nest.There is a nest of breeding each year. Each nest has 5-8 eggs. The eggs are gray blue or green. It takes about 16-18 days to incubate.The success of the chicks is late, and it takes 19-20 days to stay in the nest.