On Halloween night last year, pranksters sneaked into the student farm at Mission Viejo High School and mutilated some chickens.
This Halloween, the students were prepared.
Several times Tuesday night, they took a break from their Halloween revelry to check on the animals.
By the next morning, they thought the coast was clear.
But early Thursday, 10th-grader Son Allison arrived at the farm and followed a trail of feathers to the carcasses of 18 mutilated chickens.
The vandals had struck a day late.
"I found one chicken in a water trough, one in each of the feeders and four in the lamb barn," Allison said Friday. "Then when I was walking back, I saw four hanging from the windmill."
Two of the mutilated chickens were wounded but still alive.
"I had to put them out because one was shot in the neck and one was shot through the head," Allison said.
Some of the chickens had been shot with pellet guns, others decapitated, disemboweled and plucked, sheriff's officials said.
Sheriff's Lt. Richard J. Olson said the vandals struck Wednesday night or early Thursday.
The one-day delay apparently caught the students, members of Future Farmers of America, off guard.
"Last Halloween, the same thing happened so we were ready for them this time," said Rick Erickson, 15, a student in the school's agricultural program. "But we weren't expecting it the day after Halloween."
Olson said investigators have no suspects. "At this point, we don't know if it was some sick prank by kids or what," he said.
From time to time, vandals sneak onto the farm to take out their anger against a student or an animal. Last year, for example, an angry boyfriend mutilated another student's duck, students said. Animals also have fallen victim to loose dogs.
But the latest incident was the most gruesome.
"It's anybody's guess as to why somebody would do this," said Ron Hudson, chief of Orange County Animal Control. "It's a rather bizarre and serious type of crime as far as the number of animals and the circumstances," he said.
Although mutilated animals often are discovered at the scenes of satanic rituals, Hudson said none of the evidence points to devil worship.
"There were no burnt altars or anything left at the scene to indicate devil worship or anything like that," Hudson said.
School officials said they will offer a $300 reward for information leading to the arrest of the culprits.
"We're heartsick over it," school Principal Robert Metz said. "To have individuals do something like this is pathetic."