Yikes. I feed live all of the time and don't usually see any blood. Sometimes there's rat urine that squirts out, but that to me is grosser than blood. I used to prekill using the whack method. I would kill the rat right away with no suffering.. but WOW.. the blood was enough to make people wonder if I was a mass murderer or something, if they had walked in at that time!
I don't mind blood in itself. I have helped hang and cut up too many deer during hunting season for it to bother me much.. but it does get to some people. As long as it is not my own blood.. then we have issues!