I can't find a mention of size or weight in the pry bar link, but I do have several full-size versions of these "modern" pry bars and LOVE them.

BUT years back when hand digging for our barn's frost-proof water hydrant (many years ago) we found only one hand tool that could dig through the heavy midwestern clay --- a non-curved claw hammer. We basically used the claw like a small pick and chipped away at the stubborn clay just a bit at a time - using a shovel to remove the chips from the trench.

I never had - nor tried - using a full sized pick, but I suspect the weight would have tired us out faster in the long run.