About one third of the chickens, on their way to be slaughtered, either died in the 4 a.m. crash or were run over by cars afterward, police spokesman Stefan Jarlhage said.
Several thousand surviving chickens were freed from their cages and covered the E6 highway, one of the main roads on the Swedish west coast, he said.
The driver of the truck received only minor injuries, Jarlhage said. No other vehicle was involved in the accident, which took place about 31 miles south of Goteborg, Sweden's second largest city. It was unclear what caused the truck to flip over.
``The driver was too shocked to be questioned by police after the crash,'' Jarlhage said.
The road was still closed in both directions early Tuesday afternoon as police and rescue workers tried to remove the chickens, sanitize the road and raise the truck back up so it could be towed.