It really depends on the relative size and maturity of the prey rodent in comparison to the size of the snake. Snakes can sense when a prey item is small and/or defenseless enough that they don't have to bother with killing by constriction even though many individuals still eagerly insist on constricting their frozen/thawed food items most of the time. If you were to step up the size of the rodent, and it started to struggle when seized by the snake,.....it would instantly feel the need to use constriction to subdue the prey.
Additionally, many young hatchlings have to "learn" to constrict their prey over a period of time, as many neonates are sort of clumsy and don't have their feeding responses honed yet. I've found over several decades of working with snakes, that it's a very individual preference as to whether an individual snake uses constriction or not on prey that it doesn't really need to waste the energy on.
One thing is certain though, a wild-caught constrictor will ALWAYS constrict a larger prey item when recently taken from the wild, no matter what,....at least for a good while until it eventually "learns" that it doesn't necessarily have to continue doing this anymore......after all, since when are there frozen/thawed dead rodents laying around in nature that they would be used to dealing with?..LOL!
best regards, ~Doug
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"Better to be silent and thought a fool, than to open mouth and remove any doubt!"