OKLAHOMA CITY, 2016-Feb-04 — /EPR Retail News/ — Sonic Corp. (NASDAQ:SONC), the nation's largest chain of drive-in restaurants, today announced it will serve 100% cage-free egg products in its restaurants by 2025. Each year, SONIC purchases 155 million eggs to serve 81 million Breakfast Burritos and Breakfast Toaster® sandwiches. "Today's customer wants to know their food is…