The bloodiest feedings I've seen is where I pre-kill the rat first by thumping it over the head. Lots and lots of blood comes pouring out the nose (which is why I don't do that anymore). Live feedings can be a little bloody but usually just a few drops if anything. I rarely ever see any blood at all in feeding frozen since the blood is already pooled in the organs. The only grossness I've seen in feeding frozen is when a poorly processed rat that was half decomposed was frozen and then thawed out. They will explode when they get constricted and then you have guts all over the place, but thats pretty rare and only happens if you happen to get a really bad order of rats in which case you should be complaining to whoever you bought the rats from. So, if it really bothers you a lot, you might want to consider going with frozen/thawed if your snake will take them.

Mark