1. In the pot of a slow cooker, add diced onions and potatoes.
2. Add 2 full cans of clams with juice and 1 can without clam juice. Discard remaining juice or save for another purpose.
3. Add 1 bottle clam juice, thyme, salt and pepper to the slow cooker. Stir together.
4. Cover pot and cook on high for 4 hours.

After the 4 hours:

1. In a medium saucepan over medium-low heat, melt butter. Add in flour. Stir; mixture will be thick. Slowly add milk and the half and half. Stir and continue to cook over medium heat until thickened. 
2. Add mixture to slow cooker. Stir and cook on low for another 30 minutes. 
3. Ladle into bowls. Top with bacon. Serve with oyster or saltine crackers.