I don't do stretches before I make a shot in hunting situations, I don't do stretches before I practice.
As Friend mentioned, I do roll my shoulders (when hunting and practicing). I don't know if it helps, it does help keep me comfortable and that helps me sit still. Also, while on stand or in the blind, I draw my bow once or twice each hour if I can get away with it.
When really drilling down and doing my best to practice for hunting situations, I may only take one shot every half-hour or forty-five min. Trying to replicate that "cold-bore" shot so to speak. My opinion is that all those second, third and fourth shots really don't matter except for ensureing good form.
OkKeith