I recently started feeding my australian shepard fresh marrow bones, i know the diarea he is getting is normal, but i also have been finding ALOT of blood in his stool. Should i be seriously concered about this and take him to a vet?

Marrow bones are "recreational" not food.  If he is eating the bones  rather than just chewing off the ligaments and the joint bit then don't let him have them

should i be worried there is a splinter in his digestive system causing internal bleeding? should i take him to the vet? And the bones are just to suppliment his normal diet, he hasnt shown interest in any other form of chew toy thus far.

If you are ever concerned about the health of your dog then the vet is the best person to consult.

Dogs often bleed fresh blood if they have loose stools.  As I said before, marrow bones are not food items but will obviously be much more interesting to dogs than toys.

As Christine has said, marrow bones are for "recreation" only, mine are removed once the marrow had gone, I don't want broken teeth!  Too much marrow will trigger diarrhoea too.