Four Redwood High School seniors were suspended and could be barred from graduation ceremonies after eight chickens died and dozens more were hurt in a senior prank that went awry Thursday.

Seven chickens were found dead on campus after animal control officials were summoned by school officials about 10:30 a.m. Another chicken died later, and about 30 others were taken to the Marin Humane Society in various stages of distress.

Students apparently bought the chickens in a San Francisco Chinatown "live market" where their feet are bound to ease transporting them.

"It's absolutely horrific," said Carrie Harrington, assistant public relations director at the Humane Society. "We're horrified this has happened."

Harrington said cruelty to animals charges could range from probation and community service for juveniles to a $1,000 fine and/or six months in jail for a misdemeanor and time in state prison for a felony conviction.

She said the birds, once they have recovered, could be placed for adoption.

Sgt. Robbi Graham of the Humane Society and Assistant Principal Ben Kolb discovered seven dead chickens and others stuffed and bound in boxes in school hallways Thursday morning.

Redwood High Principal Nancy Neu said school officials believe the chickens were kept in boxes in a car in the school parking lot before they were released in the hallways Thursday morning.

"Dehydration was our biggest concern for them," Harrington said of the birds. "Chickens sometimes live in some pretty deplorable conditions. These chickens had been in pretty bad shape for some time. We're all pretty disgusted by it."

"We're absolutely outraged," Neu said, adding the school is investigating. "Our staff and our students are outraged. The students will be disciplined appropriately. It's just awful."

Neu said suspended students are prohibited from participating in extracurricular activities such as sports events and proms, and might not participate in graduation. She declined to identify the students involved.

Tamalpais Union High School District Superintendent Bob Ferguson was irate.

"Pranks are one thing, but when it results in the harm or death of animals, that's totally unacceptable," Ferguson said. "Everyone's upset about it. This was a strange idea that went way out of control. This is way beyond a prank."

Parent Lenette Viegas, whose daughter is a freshman at Redwood, said she was deeply disturbed.

"I'm still in shock, I'm speechless," Viegas said. "It's absolutely inexcusable. I don't find any humor in it at all. This is a true sense of animal cruelty."

The incident comes a year after a senior prank went awry in Novato.

San Marin High School senior Connor Andrew Reilly pleaded guilty to a felony count of vandalism last year after using a wrench to open several fire hydrants that flooded the school's library and other facilities.

Reilly was sentenced earlier this year to 60 days in jail for causing at least $140,000 in damage. He was ordered to make financial restitution and log 200 hours of community service.