METHUEN (CBS) – Hundreds of roosters are set to be euthanized after being taken from a massive cockfighting ring in western Massachusetts.

Nearly 400 birds were seized from a Northampton property last week and brought them to the MSPCA-Nevins Farm in Methuen. The roosters have to be housed separately to keep them from attacking each other and will be put down.

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Fighting roosters taken from an illegal cockfighting ring. (Photo credit: MSPCA-Angell)

“The kindest thing we can do for the vast majority of these birds is to humanely euthanize them,” MSPCA Nevins-Farm Adoption Director Mike Keiley said in a statement. “The roosters cannot be rehabilitated—all we can do now is spare them the brutal and bloody fate that awaits them in the ring.”

One-hundred-twenty-two roosters have already been euthanized but the MSPCA is hoping at least some of the remaining birds can be moved to a sanctuary.

Cockfighting is illegal but persists in an underground fashion, the MSPCA says. This is the largest cockfighting bust in the organization’s history.

“I’ve been here for 24 years and we’ve seen several cases of cockfighting though our organization, but never to this size,” Keiley told WBZ-TV. “Four hundred birds is just astronomical.”

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“Unfortunately, these animals have been selectively bred for aggression, so these animals are not able to be placed safely with other birds,” he continued.

The Nevins Farm barn is filled with cages from the top floor to horse stable. It closed to the public while the birds are there, but adoptions of other barn animals should not be affected.

Police discovered the birds after raiding buildings at the Ravenwold Greenhouses on Florence Road in Northampton.

The Ravenwold Greenhouses in Northhampton (WBZ-TV)

Ravenwold Greenhouse owner Richard Adams told WBZ-TV he had nothing to do with the cockfighting even though it happened on his property. He said the birds were taken from a building being rented out to others and wasn’t aware of any illegal activity.

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Northampton police are working to determine who is responsible. So far no charges have been filed, and no arrests have been made.