I've been feeding my BP large frozen mice every 3-4 days(what the vet recommended) to get his weight back up after the RI shots he went through. I'm almost done with the batch I bought, but I've noticed something consistent with all the frozen feedings that's different from the usual 7-10 day small rat feeding.

When he eats frozen, he always seems to be drawing quite a bit of blood from the corpse. When he swallows them, I notice residual amounts of blood remaining within his mouth(it disappears after he swallows, so I know he's not bleeding). Sometimes the mouse is coated entirely with its own blood. Is this pretty common? Or am I making them too soft when I boil them?