5* Eventer Conquers Sinusitis Jan 29, 2021 David Britnell, equine health, Equine nutrition, Eventer, eventing, Exercise, Flexineb, hay steaming, Haygain, Haygain Riders, Haygain team, Sinusitis David Britnell’s Equine Eventing Partner Overcomes Sinusitis with Steamed Hay & Flexineb's Help.