  We solve the long-time dynamics of a high-gain free-electron laser in the
quantum regime. In this regime each electron emits at most one photon on
average, independently of the initial field. In contrast, the variance of the
photon statistics shows a qualitatively different behavior for different
initial states of the field. We find that the realization of a seeded Quantum
FEL is more feasible than self-amplified spontaneous emission.
