No assumption here, have experienced it first hand.I think why all of us here ASSUME we have to let them rest is because most of the people on here will process many chickens at one time ...
I find rigor sets in pretty darn quick...within 10 minutes after kill leg joints are stiff as hell when I gut after plucking. have also cooked a bird the day of and one day after, much tougher meat than if I let cleaned carcass sit for 2-3 days...that's on layer birds, not CX.
Also with butchering fresh turkeys, much easier to butcher into parts 4-5 days after kill than 2-3 days. Rigor is real.
...and do they really remember how tender or tough that bird might have been?my parents told me they would get a chicken (or 2 or 3) for sunday dinner and butcher them and fry them up or cook them some other way immediately