The name of the owner of the farm was unavailable.
Dozens of firefighters responded to the blaze, which burned into the night and sent up a plume of thick black smoke that could be seen from as far away as Reading and Wyomissing.
Some of the first firefighters who arrived reported that the barn was engulfed in flames.
Some livestock escaped but many cows that were tied inside the barn perished, firefighters said. The number of dead animals was 78 or 79, officials said.
A tanker task force responded and shuttled water to the scene from a nearby pond.
Fire police closed roads in the area, and fire trucks and other vehicles clogged the country roads.
A large number of firefighters and emergency workers were still at the farm more than six hours after the fire was discovered.
They were preparing to use heavy construction equipment late Wednesday to move the rubble and carcasses and extinguish hot spots.
The cause of the fire is under investigation.
No damage estimate was available.
Written by Reading Eagle