Police and RSPCA officers raided an address in Ilford and disrupted a suspected organised cockfight in an outbuilding.
A cockerel's blood was found splashed across a fighting pit, which had seats around the edge as a viewing area, and 10 cockerels and two hens were seized.
Several of the cockerels had injuries consistent with fighting, one was found to have sharpened spurs - a common cockfighting tactic - and the cockerels acted aggressively towards a dummy bird used as a training aid.
Five men were convicted at an earlier trial of animal welfare offences and they were sentenced at Barkingside Magistrates' Court in east London on Thursday, the RSPCA said.
All were banned from keeping birds and sentenced to a 200-hour community punishment order.
The men found guilty of being present at a cockfight on January 2 are: Mohamed Arif, 44, of Fairfield Road, Ilford; Akhtar Hussain, 47, of Greenhill Grove, Manor Park; Mehtab Ahmed, 41, of Celebration Way, Highams Park; Mohammed Asab, 51, of Water Lane, Ilford; and Altaf Hussain, 54, of Parkstone Road, Coventry.
Asab was also found guilty of causing an animal fight, training animals for use in connection with an animal fight, keeping a premises for use for an animal fight, and causing unnecessary suffering to a cockerel.
He was handed a 22-week suspended sentence, ordered to pay £12,000 costs and had his birds and cockfighting items confiscated.
The other men were ordered to pay £1,500 costs each, and Arif was ordered to hand over his birds.
RSPCA inspector Cliff Harrison, who led the investigation, said: "Cockfighting is an abhorrent and cruel practice which was outlawed almost 200 years ago.
"To take enjoyment from watching two birds inflict such horrendous - and often life-threatening - injuries on each other is something that should be well and truly confined to the history books."
The evidence suggested the men were there to watch and bet on the fight, he said, adding that photos and videos of cockerels being trained and of a champion trophy presentation were found on seized mobile phones.
"This was vital in proving that this group was part of an organised ring of cockfighters who operated this sickening league - with the birds paying the ultimate price," he said.
The seized birds, all aseel or asil types originating from India and Pakistan, are in RSPCA care and will be re-homed.