Not in that Big Mac! McDonald's is toying with the idea of messing with a classic by changing up the Big Mac -- replacing those two all-beef patties with two all-chicken versions. If you want to test out the poultry patties, you'll have to travel. As of now, they'll only be available in Canada, The limited-run sandwich mimics the original, but for some reason, contains no onions. So, if you're looking for a fast-food adventure, make a run for the northern border now.