Assessment of Welfare in Groups of Horses with Different Management, Environments and Activities by Measuring Cortisol in Horsehair, Using Liquid Chromatography Coupled to Hybrid Orbitrap High-Resolution Mass Spectrometry Cerasoli, F.; Podaliri Vulpiani, M.; Saluti, G.; Conte, A.; Ricci, M.; Savini, G.; D'Alterio, N. Animals 2022, 12, 1739