In a large soup pot, skillet, or a slow cooker with saute/brown function, add the butter over medium heat.
Once melted, add the onion, carrots, and celery. Season with salt. Cook until softened, about 10 minutes.
Add the garlic and cook another minute.
If using a soup pot or skillet, transfer the vegetables to a slow cooker.
Add the chicken, thyme, and broth. Cook on high for 8-12 hours.
Remove the chicken from the soup and take the meat off the bones. Discard the skin and bones. Shred the meat.
Puree the broth with an immersion blender or a regular blender.
Add the meat back to the soup along with the pasta. Cook on high for 30 more minutes or until the pasta is tender.
Serve and enjoy!