What happens if a cuckoo throws its egg into a nest where chicks have already hatched?

The cuckoo is an insidious bird. She lays an egg in the nests of other birds so that they feed and raise his chick. The cuckoo is an intelligent bird, and although she herself does not raise her chick, she is still not indifferent to the fate of the future chick. For this reason, a cuckoo will not lay its egg in a nest in which chicks have already hatched. After all, birds will not hatch a single egg for a long time to the detriment of live, already hatched chicks. Life in nature is very harsh. Birds lay several eggs with the expectation that one or two will survive. Some birds even throw weak chicks out of the nest so that the stronger one survives and gets stronger. Therefore, if a cuckoo tosses an egg into a nest where chicks have already hatched, its egg will most likely be discarded.