Multi‑behavior recognition and health assessment of laying hens using RSA‑YOLO under welfare‑oriented farming

In welfare-oriented farming, laying hen behavior is a critical health indicator, yet automated assessment is often limited. This study introduces a framework for multi-behavior recognition and health assessment using an improved RSA-YOLO model. By integrating RFAConv, C3k2_KSFA, and ATFL loss into YOLOv11n, the lightweight model (2.75M parameters) achieved 88.3% mAP@50 for six behaviors (standing, feeding, roosting, preening, feather pecking, resting), outperforming baseline models. A Health Composite Index (HCI) was developed, weighting feeding, movement, and resting behaviors. A pilot study revealed a healthy reference cage had a superior HCI (98.2) and feeding ratio (32.6%) compared to a cage with mortality (70.1 and 12.4%, respectively). In this pilot study, significantly, behavioral changes, such as decreased feeding, preceded a drop in egg production by approximately one week, demonstrating the framework's early-warning potential. This research offers an automated, quantitative tool for on-farm health monitoring in poultry farming.