Matthew Ronneberg, Thomas Cavanaugh and Matthew Mercuro, all 18, were arrested for the bludgeoning deaths of three emus, three ducks and two rheas at the Popcorn Park Zoo.
Authorities say the three were out joyriding and jumped a fence at the zoo and attacked the animals with a rake and a length of plastic plumbing pipe.
The birds were found dead in their pens Monday morning. One duck's eye was gouged out and the emus had their windpipes crushed, jugular veins slashed and were beaten on their heads.
Lacey Township police say a series of tips led them to the three suspects.
The slayings capped a night that authorities said began with an attack on a duck or goose at a county park. It allegedly continued with an arson-and-graffiti spree at a paintball facility and included vandalism at a church, where $5,000 worth of stained glass windows were shattered. The animal at the park survived.
The teenagers were each charged with eight counts of cruelty to animals and one count each of burglary, criminal trespass and criminal mischief for the zoo attack. In neighboring Manchester Township, site of the paintball facility and church, they face burglary and other charges.
Police Capt. William Nally said there was no motive beyond the suspects' "morbid sense of entertainment."
"They were out riding around, looking for things to do," Nally said.
Each count of cruelty and criminal mischief is punishable by up to 18 months in prison, and the three could face five years for burglary. They were being held on $50,000 bail, and did not yet have attorneys.
By John Curran