The animals were believed to have been killed late Thursday or early Friday at the Catherine Ferguson Academy on Detroit's west side. A cat also was found dead.
"It looks like some crazy person had gone crazy on the animals," school principal Asenath Andrews said Friday. "They were fine when we left yesterday. They're all dead today except for one chicken and one cat."
A volunteer who helps students take care of the farm found the animals Friday morning.
Young women with children ages 3 and younger also are enrolled in the school, which is operated by the Wayne County Regional Service Agency.
No classes are held on Fridays and no students were around when the dead animals were found.
"I'm worried about the girls," said Andrews. "The animals belong to the girls. The girls belong to me. I'm worried about them, not the animals. I'm worried about their safety."
Students at the charter school work the farm and sell their produce to area farmers markets.
The Michigan Humane Society is investigating the animals' deaths.