Interestingly, ATK's dumpling soup recipe suggests using a rotisserie chicken to keep the flavor while decreasing the cooking time.
We had a lot of chicken frozen in our chest freezer, so we decided to use that and poach it in the chicken broth and vegetables instead. Yes, it does take a little bit longer than using a cooked rotisserie chicken, but it's just as flavorful.
The poached chicken turned out quite well and had enough flavor for us. The rest of the soup was classic, with a mire poix and chicken broth, salt and pepper. We thought it could have used a bit of thyme or some other earthy note to deepen the flavor.
There is such a great feeling when you bite into a hearty dumpling that is accompanied with some savory chicken soup broth.