While I personally am a fan of their food and the way they treat employees in comparison to other fast food places, despite my displeasure in some of management's social agenda, some locations do have employees that work on Sunday.

My cousin used to work as a supervisor during college for a franchisee with about five different locations, she'd float amongst locations. She used to routinely be called in to unload delivery trucks in the early morning Sun or late Sun at night for about six hour shift. The franchisee would always make sure they had a break to attend church service should they choose, but they would work on Sun. If he know someone was providing a ride for one of his employees to work on a Sunday, he would extend an offer for the car's occupants to come inside and eat something complimentary before returning home.