Specifically, adult customers who wear any type of cow attire, whether it's a full-on cow costume or just a cow-spotted handkerchief, will get a free entree of choice while children will get a free kid's meal for putting on cow attire. In past years, you got a complete meal for a full-on cow costume but I guess they're looking to simplify the process.
The event runs from each location's opening through 7 PM local time.
Image via Chick-fil-A.