Flocks of sentinel chickens on duty to provide early warning of deadly virus as rains brings mosquitoes MonMonday 22 updated MonMonday 22 FebFebruary 2021 at 6:17am Kevin Rosser is happy to volunteer to look after the sentinel chickens in Hay and says the supply of eggs is a bonus. ( Print text only Cancel A humble chicken coop in Hay in southern NSW is playing a key role in an early warning system for a rare but deadly virus. Key points: Flocks of sentinel chickens are used to see if Murray Valley encephalitis is present in the mosquito population. The chickens are looked after by volunteers