Preheat your oven to 375°F (190°C). In a large skillet over medium heat, sauté the zucchini, yellow squash, red bell pepper, onion, and garlic in olive oil for 5-7 minutes, or until the vegetables are tender. Remove the skillet from heat and stir in the dried thyme, dried rosemary, salt, and pepper.

Cut a pocket into each chicken breast, being careful not to cut through the other side. Spoon the vegetable mixture into the pocket of each chicken breast, distributing the mixture evenly.

Place the stuffed chicken breasts in a baking dish, and bake for 20-25 minutes, or until the chicken is cooked through and temps at 165 deg F. Let cool for a few minutes before slicing and serving.