It's even worse, if you buy "cold" rotisserie chicken (literally the same just not kept warm under heat lamps so you have to warm it up if you want it hot) it was $2.77 last time I bought one at Walmart.
Why the price difference? Don't know. It's stored in the open cover "cold food storage" they use it which are probably similar cost to run as the heat lamps. That said for a chicken sandwich or chicken noodle soup such a better deal.