The Napa County Sheriff’s Office is investigating an operation it says trained roosters in the Carneros area to take part in illegal cockfights, and its alleged owner faces potential charges of animal cruelty and illegal gun possession.

Deputies served a search warrant April 18 on a property in the 1200 block of Thompson Avenue, where they found two dozen roosters that apparently were being trained and physically altered to attack other roosters, according to sheriff’s Sgt. Frank Walsh. Thirteen of the birds had combs, wattles and spurs shaved, trimmed or spurred for fighting purposes, and those roosters were taken to the Napa County animal shelter, Walsh said Thursday.

The county district attorney’s office is investigating Arturo Covarrubias Jr., a 44-year-old Napan, on a possible misdemeanor count of possessing trained birds for fighting purposes. Covarrubias also may face a felony count of assault rifle possession after deputies found an AK-47 and an AR-15 at the Thompson Avenue property, according to Walsh, who said deputies also recovered several hunting rifles and a revolver — all of them unregistered.

Neither Covarrubias nor any other people were present when deputies visited the site, according to the sheriff’s office. His name did not appear in booking records for the Napa County jail as of Thursday afternoon.

Walsh, a member of the sheriff’s office’s problem-oriented policing unit, said he began receiving complaints of unusual rooster noise on Thompson Avenue in February.

When roosters are trained to be aggressive to their peers and to fight them, “the crowing will be 24/7” instead of taking place at certain hours of the day, according to Walsh. “When neighbors were complaining about hearing rooster noise all night long, it was an indication to me that something might be going on,” he told the Napa Valley Register.

Observation of and visits to the Carneros property revealed that male birds were being housed in a way that suggested training for fighting purposes, Walsh added. Those signs included housing each bird in a 55-gallon metal drum and tethering the animal with a bungee cord to the ground outside — and spacing the drums to allow roosters to behave aggressively toward other roosters without physically harming them.

Combs atop the head and wattles at the neck were ground down to lessen the chance of injury from blood vessels massed around the bed, according to Walsh. Spurs were filed and trimmed to allow roosters to hold a blade or another fighting tool, he said.

The altered roosters that were moved to the county animal shelter appeared to be well-fed and well-kept and may have been raised for sale, according to Walsh, who reported no signs of a cockfight ring or combat activity on the property. Eleven other male birds were not seized because they were physically intact and appeared to be paired with hens for breeding.

While the would-be fighting birds may not have been deprived of food or shelter, “the mutilation of them for fighting falls into the cruelty category,” said Walsh.

The suspected cockfighting training site is a leased 2-acre ranchette that Walsh said could comfortably be looked after by one person — on a far smaller scale than other operations that have been seized elsewhere in California. In 2022, for instance, “Chicken” Joe Sanford received a 16-month federal prison term after the discovery of a breeding operation with more than 2,900 gamefowl on his farm in Ceres, which prosecutors said sold birds as far afield as Peru and the Philippines.

State legislation introduced in February aims to toughen penalties for cockfighting, not only to protect roosters from blood sport — cockfighting is illegal in all 50 states and the District of Columbia — but also to slow the spread of avian flu. Assembly Bill 928 would outlaw keeping more than three roosters per acre or 25 total roosters on a property, with exemptions for commercial poultry farming, hobbyists, schools, and FFA and 4-H clubs.