They may just be confused about what they heard, or they heard that from someone confused.
Something I heard, which sounds more plausible, is: rotisserie chickens that have been sitting around a bit (not even close to going bad, just not very hot and fresh anymore) are used to make the things they sell with rotisserie chicken in them, like those trays of chicken and broccoli Alfredo. (I can eat an embarrassing large portion of those "family size" trays.)
I could see how after being passed through a few people that turns into what they said.