SOLANO COUNTY (CBS SF) — Solano County’s watch tower in the battle against the West Nile Virus is actually a chicken coop.

The coop is located on the edge of the Suisun Marsh, the breeding ground for the Culex Tarsalis mosquito, the carrier of the disease that causes fever, body aches, skin rash and swollen lymph nodes in humans.

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The 12 ‘sentinel’ chickens housed in the coop have intentionally been made sitting ducks for the mosquitoes. Warm-blooded targets for a bite that will infect the birds.

“We get bi-weekly blood tests from them and they let us know if they have mosquito-borne illnesses that can be transmitted to human beings,” said Waite Colbaugh of the Solano County Mosquito Abatement District.

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Unlike crows and ravens, which will die after being bitten, chickens have a natural immunity. So if their blood tests show West Nile antibodies, the county knows the virus is in the area.

In Solano County, there are three flocks spread around in high-risk areas and Waite calls them his agency’s canaries in the coal mine, giving officials an idea of where to focus their abatement efforts.

“They’re actually really fun to work with,” Colbaugh said. “I really like working with them. They all have their own personalities. Everyone at the district tends to get attached to one or two chickens.”

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But not too attached because in the Fall, when West Nile season ends, each hen is offered to the public for adoption and a future befitting a life-saving heroine.