To retrieve logs from a failed replica in SkyServe, you can use the sky serve logs command with the service name and replica ID. This command allows you to stream the logs of a specific replica, providing insights into why the replica failed to start. Additionally, running sky launch service.yaml to launch a single replica can help troubleshoot before scaling up with sky serve up. Adjusting the initial_delay_seconds in the readiness_probe configuration can also be beneficial for services requiring longer initialization time.