At least 40 chickens were killed when the truck they were being transported on crashed on the N1 freeway north of Johannesburg on Thursday, the Johannesburg Metro Police Department (JMPD) said.

The accident happened just before midday between Allandale Road and the Buccleuch interchange.

JMPD spokesperson Chief Superintendent Wayne Minnaar said about 60 other chickens had been rescued.

Minaar said the cause of the incident would be investigated.

Two people had been injured in the crash. They had since been taken to hospital.

The SPCA were also on the scene.

The road had since been reopened for traffic.