Cook the chopped bacon in a skillet over medium heat until crisp. Remove the bacon with a slotted spoon and set aside, leaving 1 tablespoon of the drippings in the pan.
Add the diced onion to the skillet and cook in the bacon drippings for 3 minutes until softened.
Place the potatoes, corn, chicken broth, thyme, salt, and black pepper in the slow cooker. Add the cooked onion and half of the crisp bacon.
Cover and cook on low for 6 hours or on high for 3 hours, until the potatoes are tender.
Stir in the heavy cream and let the chowder cook for 15 more minutes on low.
Ladle into bowls and top with the remaining bacon and fresh parsley.