My Sinaloan eats F/T but he never constricts the prey and justs starts eating it as soon as I put it in his cage. I have also seen both Black Racers and Coachwhips do this very same thing. They will usually grab the mouse or rat and then shake it a few times maybe to stun it and the begin eating it alive. I guess it is a normal thing with them. My other snakes constrict the F/T prey before eating it expect of course for mt Canebrake and Copperhead.