I'm not concerned about the nutritional value of blood worms as I know fish love them and they aren't a "complete" food. In my human vocabulary I see them as kind of the equivalent of "potato chips" (all season preferred). In a day, the fish get two bouts of Omega One flake food and a frozen "potato chip" (I speak metaphorically here) at one of the sittings.
So if the fish gets a half a blood worm or a whole one, I'm not concerned as the main nutrition is in the flake and some of the other frozen foods I feed them which are very well balanced (the San Francisco Bay brand varieties). Also there are some whole worms even in the cut version, not all the worms lay down horizontally to die, side by side, if you know what I mean, so even a smaller portion will have some whole worms.
But Byron if you are concerned about whole versus cut up worms, you must have very cared for fish - the lucky guys and gals.