Add bacon to a large Dutch oven, and cook over medium heat, stirring often, until crisp, about 9 to 10 minutes. Use a slotted spoon and remove to a paper towel-lined plate. Keep rippings in Dutch oven.
Add onion to drippings in Dutch oven, and cook, stirring often, until softened and translucent, about 4 minutes. Add garlic and crushed red pepper, and cook, stirring constantly, until fragrant, about 1 minute.
Add onion to the Dutch oven, and cook until translucent, about 4 minutes. Add garlic and crushed red pepper, and cook stirring constantly about 1 minute.
Add green beans, chicken broth, salt, thyme sprigs, and bay leaf and bring to a boil over medium-high heat. Reduce heat to low and cover and simmer until green beans are very tender, 40 minutes to 1 hour. Mine were done at 40 minutes.
Stir in the butter and cooked bacon and cook until heated through and the butter is melted, about 1 minute. Remove from heat and discard bay leaf and thyme sprigs. Serve with a slotted spoon.