A 56-year-old driver was taken to hospital after his tractor trailer hit four horses that had escaped from a nearby farm onto Churchill Line near Telfer Road.
The man suffered from non-life threatening injuries, say Sarnia Police.
One of the horses was killed immediately but two of the other three had to be euthanized. One of the horses had returned to the farm without injury.
The truck left the road and went through fences. It narrowly missed hitting a gas line before hitting a hydro pole.
The road was closed for some time before Bluewater Power was able to restore hydro.