Chick-fil-A is on fire. The fast-growing chicken-sandwich franchise is poised to become the third-largest fast-food chain in the country next year by sales, replacing Subway, according to Kalinowski Equity Research. Chick-fil-A would leapfrog past Taco Bell, Burger King and Wendy’s, the No. 4, 5 and 6 chains respectively, according to the firm.