It will transfer its business to the new Sofina Foods plant at Mitchell.
There are about 350 union members working at the Thamesford plant, east of London.
It was developed by Cold Spring Farms Ltd. under the leadership of the late Harvey Beaty.
Schneider Corp. bought Cold Spring Farms, then Maple Leaf bought Schneider Corp.
In 2013, Maple Leaf sold its turkey quota and farms to the Schlegel family of Kitchener as part of its long-term plan to concentrate resources on meat processing at a new plant at Hamilton.
It sold its turkey breeding farms and hatchery to Cuddy Foods Ltd. at the same time, but kept the processing plant at Thamesford.