Complex sentence: Twinkie production in the United States will be back on shelves by middle June, but it is still being produced in Canada by Saputo Incorporated's Vachon Inc. (at a bakery in Montreal) which owns the Canadian rights for the product.
Split into simpler sentences: Twinkie production in the United States will resume and be back on shelves by middle June. It is still being produced in Canada by Saputo Incorporated's Vachon Inc. (at a bakery in Montreal) which owns the Canadian rights for the product.