The transport truck caught fire around 2:45 a.m. on the westbound 401 near Mavis Road in Mississauga.
Firefighters managed to extinguish the blaze, which appeared to originate in the rear of the trailer.
Police officers and other first responders pulled chicken cages off the burning truck and tried to corral birds that were running free near the roadway.
Eventually, after several hours, the chickens were loaded onto a second truck and the roadway was reopened.
Officials didn't say how many birds died in the fire.