PHILADELPHIA (AP) -- Monday mornings are hard enough. Imagine finding 50 chickens running loose in your high school. Workers arriving to open Northeast High School in Philadelphia found dozens of hens and roosters wandering around the hallways. The birds were apparently brought to the school sometime over the weekend, said school district spokesman Fernando Gallard. "We don't know where the chickens came from or who they belong to," Gallard said. "I'm pretty sure there is a very upset poultry farmer somewhere who wants them back." The floors were covered with droppings and chicken feed. Most of the school's 3,600 students were sent home for the day because the school required extensive cleanup, he said. A farmer was called to round up the birds and bring them to Fox Chase Farm, the district's agricultural school, Gallard said. Police are checking surveillance tapes to see if they can determine the perpetrator of the fowl prank. The culprit will have to pay a hefty fine, said Gallard. "It's not going to be chicken scratch," he said.