Nah, as an occasional treat, it won't hurt 'em, really. They love soft bread!
I was just mentioning that I have other, healthier treats for my own birds. I try to make sure they get plenty of protein and greens. I also don't want to transport a mini-meal McDouble over fifty miles home for the chickens. But the city free range, probably feral chickens get that exact thing a couple times a week from me.