Though tolerated by Saddam Hussein, fans of the blood sport had to bribe policemen to indulge in gambling, an important part of the cockfighting routine.
However, the fans are having a great time since Saddam was ousted, as they are free to openly play the odds while the roosters fight to the death.
Cockfighting and the associated gambling are serious business in Iraq. Die-hard followers of the sport drive from across Iraq to Baghdad.
People like Kathim Jassim, Baghdad's king of cockfighting, are immensely popular and treated with respect.
On one recent night, the betting started at $50 in a country where monthly salaries rarely exceed $100.
A rooster owner from the holy Shia city of Kerbala, where gambling is prohibited, explained why he could not stay away.
"I feel like I am the one fighting when my rooster wins," he said.
Fight to death
At a typical cockfight, the roosters flap their wings in frenzy and go for each other's throats with super-sharp claws as the crowd roars its approval and the odds shoot.
Animal rights groups would shudder at the sight of roosters fighting to the death or gouging out each other's eyes.
"It is inhuman. The rooster's neck or nose or wing is broken or it dies. But we Iraqis are used to blood and force"
But the common Iraqis, traditionally used to the sport, do not understand why Western countries make a fuss over animals.
"It is inhuman. The rooster's neck or nose or wing is broken or it dies. But we Iraqis are used to blood and force," said Thia Sayyid, who trains and sells roosters in a poultry market in the poor Bayaa section of Baghdad.
The training regimen of these winged fighters would make any sportsman proud.
To strengthen the leg muscles, the roosters are placed on exercise wheels. They are kept away from females to keep them angry and primed for action.
At the age of one, the birds are placed in fighting pits for periods of five, 10 and 15 minutes to prepare for gruelling encounters that can last for two hours.
In some countries, the claw nails are cut off and replaced with metal. Iraqi trainers say that would be too cruel.
"This is an Islamic state. We would not do that," said Faris al-Qaisey, owner of The Ancient Casino in Baghdad, the capital's most popular cockfighting venue.
Taxi drivers, engineers, accountants and labourers pack his grimy coffee shop every night as roosters size up their opponents. Some of the birds are imported from Turkey, Syria, Jordan and Thailand.
The spectators on this particular day are ordinary men from all walks of life.
The more the roosters tire, the more the audience jumps and screams, waiting for the kill.
Elderly men puff on water pipes, as the exhausted roosters take 60-second breaks between 15-minute rounds. Not everyone can handle the violence, but the tradition seems sure to continue from one generation to the next.
"I don't like the blood. But I love to watch," said 12-year-old Mustafa al-Amiri, as his father raised his bet.