The blood sport involves attaching razor sharp barbs to the bird's leg, then forcing them into a violent death match.
The video shows a field in Fontana where police and animal services officers raided a chicken coop. Inside is an illegal cockfighting training camp cramped full of roosters bred for battle.
"It's part of a culture almost where not only there is the illegal gambling of course, the inhumane treatment of animals is occurring, but you got drug deals going on, you have gangs getting involved," said Miachel Ramos, the San Bernardino County district attorney.
For the participants it is a shadowy world of high-stake bets and matches. For the animals involved, it is torture.
"There's no winners in cockfighting," said Jamie Simmons, an animal control officer. "The animals are left to bleed out, thrown in a six-foot hole, where they will die, suffer a horrific death."
Some roosters are injected with steroids and teased with other birds before they are taken away to the fighting ring.
"This is an on-going problem," Simmons said. "We don't see that it has slowed down. If anything, it has increased."
Cockfighting is illegal in all states and a felony in 39 of them. In California, it's a misdemeanor. Ramos is hoping to change that.
"Next time I meet with the governor I'm going to talk to him about this," Ramos said. "We really need to increase the punishment for this."
The D.A.'s office is fighting back with the help of the Humane Society of the United States, which is offering a $5,000 reward for information leading to the arrest and conviction of anyone connected to illegal cockfighting.
The number to call is (877) 847-4787.