Flying Ad Hoc Networks operate under extreme mobility, fluctuating node density, frequent link disruptions, and strict energy constraints, which jointly degrade routing stability and communication reliability. Existing FANET routing approaches address these challenges in isolation through learning-based adaptation, clustering, or bio-inspired heuristics, leaving coordination among zoning, relay selection, and energy regulation insufficiently explored. This work introduces a Krill Herd Optimized Zone Routing Protocol that embeds collective swarm intelligence directly into zonal routing control. New knowledge is created through an optimization-governed routing framework where krill herd dynamics regulate zone radius adaptation, relay selection, hop progression, and spatial stability within a unified routing architecture. The contribution advances routing-system design rather than proposing a new optimizer, enabling stable and energy-aware communication under ultra-dynamic aerial conditions. NS3-based evaluation across varying node densities demonstrates reduced delay, lower packet loss, improved packet delivery, higher throughput, and controlled energy consumption compared to existing protocols. Results confirm the effectiveness of optimization-driven zonal coordination for sustaining quality of service in highly dynamic FANET deployments.