What follows is what I remember eating at the Eden Roc in Miami Beach 40 years ago and what I served when was a busboy in the Catskills 35 years ago. keep in mind that hotels make and serve Chicken Fricassee to use their leftovers. The recipe is meant to be made with cheap chicken parts. It's cheaper and better that way. It's best served over rice or egg noodles, but is fine to eat on its own.
Chicken backs are bone and fat -- and little meat -- that's between a chicken thigh and the chicken leg. There's a lot of flavor there.
When made with boneless chicken thighs in a slow cooker without the gizzards and hearts, its more conventional and makes a great sandwich.