Friday is more than just the 13th. It is Cow Appreciation Day at Chick-Fil-A.

In honor of this unofficial holiday, Chick-Fil-A restaurants across the country are offering you free chicken if you show up dressed like a cow. 

Show up partially dressed like a cow, which means rocking a cow accessory like a printed vet, hat or purse, and you get a free entree (breakfast, lunch or dinner). 

If you make the effort to fully dress like a cow from head to toe, Chick-Fil-A will give you a free full combo meal (breakfast, lunch or dinner). 

Wondering how to dress like a cow on a budget? Chick-Fil-A offers tips like wearing all white and then just adding spot. They even have a "cow starter kit" available for download. 

Starting Friday, enter your cow costume pics at Chick-Fil-A.com or through their mobile app for a chance to win a $100 gift card, a catered Chick-Fil-A party and other prizes. Winners will be awarded in three categories - Cow (one person age 13 years and older), Calf/Calves (one or more children ages 12 or younger) and Herd (two or more people, one must be age 13 or older). 

So, who is going to dress like a cow on Friday?