How long has your hen been laying? Is she in her first season?
My own experience has been that a blood-smeared egg can be caused by:
* young layers
* exceptionally large eggs
* eggs with tiny calcifications on the outside of the shell
* hens rushing to squeeze the egg out, usually from nest box squabbles
Just to play it safe, you might take a quick look at her bum just to make sure she isn't eaten up with mites, or that no one is picking her behind. If the vent looks nice and pink, bug-free and no feathers seem missing (and you see no blood or wounds), you should be good to go.
Good luck, and please keep us posted on how she does!