First, I cannot stress the need to make the condensed soup yourself. It is not a only a cost saver, you know what is in it. It is so easy and I have a shortcut recipe for this on the site that I have made many times. Also, use the chicken stock powder instead of canned stock or make fresh stock yourself from a chicken carcass or from a previous chicken recipe.
Pour the undiluted condensed soup and the stock into the slow cooker and add the bay leaf and chopped celery, stir to combine then add the chicken into the broth mixture, cover and cook on High setting for 3 hours or Low setting for 5-6 hours.
Remove the chicken, if using just breasts, shred with two forks into bite size pieces and return to the slow cooker, and if using thighs, using two forks, remove skin and bone and set aside (great treat for your dog), then shred with the forks into bite size pieces and return to the slow cooker. Or feel free to use a combination of the two. Remove the bay leaf.
About 20 minutes before the chicken is done (either on High or Low setting), boil a pot of water and cook your egg noodles or Fettuccine (which is what I will use) and the chopped carrot together. Drain and set aside. The reason for cooking the noodles, or pasta, separate is to prevent them from becoming mush.
After the chicken is shredded and returned to the slow cooker, stir in the egg noodles or fettuccine pasta and carrots and heat for another 30 minutes, stirring once in a while as well, until heated through. Serve.