Thanks for that link @Molpet; very interesting and useful.Is it a young bird? They don't need to be hung. I keep plucked and gutted older turkeys in the refrigerator for a week to help tenderize.
I have kept old chickens intact until rigor mortise passed or I forgot one for a week before I plucked and gutted. She was good.
Some people have an ick factor about refrigeration or hanging intact birds.
https://honest-food.net/on-hanging-pheasants-2/
I have no idea how old the offender is, so I plan to refrigerate for the recommended minimum 3 days.
I'm working on the assumption that 'hanging' horizontally is OK, as there is no way to hang it vertically in my fridge. I guess the term comes from historical use when it was easier / more efficient / safer to hang meat from a ceiling than lay it on a shelf in a dedicated meat store, rather than from any biological reason, given that the bird is intact and could be hung up or down ("Hanging your birds by the neck or feet does not matter, as several studies has [sic] shown.").