I make a version of this but it's not for anyone counting calories! I line the bottom with sliced baby carrots, onion chunks, and celery (especially the leaves). I add about a cup of water, toss the chicken on top and cook 5 hours.
At that point, I remove carcass and pick through the chicken, making bite sized pieces. I also strain the liquid at the bottom to remove the veggies, and I set these aside. I return the liquid to the crockpot, along with the chicken chunks or pieces. Then I return the carrots to the crockpot, along with some of the celery for flavor. I try to make sure the leaves are included. I don't usually return the onion, but if I do, I cut it in much smaller pieces.
Then I add chicken broth, usually 3-4 cans. I dump in a little more seasoning - mainly salt, pepper, sage and sometimes onion powder if I remove the onions. I also add about a cup or 1.5 cups of rice. Lately, I've also added corn to it. I set it on high and let it cook until the rice is done.
You can stop here or do what I've done in a couple recent batches, which is add a basic white sauce if you want it to have a creamy component. Take about 3 T butter and bring to full boil. Add 3 T flour and cook thoroughly. Slowly add in a cup of milk and get it fully thickened. Then start adding to your soup until it's the desired consistently. You definitely need to add more salt if you do this.
It sounds like a lot of work, but it's one of those recipes that takes 6 hours, with about 15 minutes prep time.
I'd been meaning to write this down, so thank you for the opportunity