Using a knife, score the pork roast on the fat side. Mix together rosemary, thyme, garlic powder, salt and pepper in a bowl. Using a pastry brush, spread the oil on all sides of the pork roast.
Season each side by sprinkling seasoning on the roast. Place into the slow cooker and add chicken broth. Place the lid on the slow cooker and cook on low for 6-8 hours or high for 3-4 hours until internal temperature reaches 160 degrees.