Pre-heat oven to 425 degrees. Spray small, individual bread pans with cooking spray, then set them on a baking sheet. Set aside.
Pour 1 cup of chicken broth into a small to medium saucepan and bring to a boil. Add the raw chicken pieces to the broth and allow to simmer over medium heat until cooked, ~10 minutes or until the internal temperature reaches 165 degrees.
In a separate saucepan, melt the butter over medium heat. Add the diced onions and cook until soft, ~2 minutes, then stir in the minced garlic. Next add the milk, chicken broth and the whole wheat flour to the sauce pan with the onions and continue to stir until the flour is combined and the liquid starts to thicken. Once simmering, add the salt, pepper, rosemary and frozen mixed vegetables. Stir and continue to cook until the mixture begins to simmer.
When the chicken is done, use thongs to remove the chicken pieces and place them in a separate bowl, then pour the chicken broth into the saucepan with the mixed vegetables. Use the thongs or a fork to shred the chicken, then add it to the sauce pan with the cooked vegetables. Stir well to combine all of the pot pie filling.
Spoon the chicken and vegetables evenly into the four individual pans and set side.
Unroll the refrigerated pie crust and cut in half. You only need ½ of the crust for this recipe, so re-roll the unused portion and return it to the refrigerator. Use your hands or a rolling pin to shape the crust into a long rectangle, then use a knife or pizza to slice it into 4 even rectangular pieces. Place a piece of crust over each of the 4 individual pot pie pans, then use your fingers to seal the crust over the sides. Once sealed, use a sharp knife to make a slice down the center of each pie.
Transfer the baking sheet with the individual pot pies to the oven and bake at 425 degrees for 20-25 minutes.