By Daniel Kline The fast-food favorite is only being sold for a limited time. Fast-food chains have only so much capacity for new menu items. When you only have a few fryers, one grill, and limited preparation space, choices have to be made. That’s why McDonald’s (MCD) – Get McDonald’s Corporation Report franchisees pushed back at the chain’s efforts to offer all-day breakfast. Customers may want it, but adding it complicates food preparation as there’s simply only so much space in each restaurant’s kitchen. It’s this problem that explains when many fast-food limited-time-offers use a new ingr…