I think the younger the bird the less resting is needed.
I imagine putting the processed birds in the freezer is easier(maybe safer, maybe USDA 'rules') when dealing with large quantities.
Not sure if resting after freezing and thawing is the same as resting a fresh carcass.
@Chef JimmyJ had some knowledge on that IIRC.
The whole resting/brining/freezing/cooking ...many different regimes creating different end products would be hard to 'test' thoroughly enough for true comparison quantification.
Am curious about it tho, cause I always 'think things to death'