Pat chicken dry with paper towels. If using breasts and if they're large, cut each one in half with kitchen shears.
Heat the olive oil in a large, heavy dutch oven over medium heat. Add half of the chicken pieces to the pan. Cook until browned, 4-5 minutes on each side.
Transfer the browned chicken to a plate. Repeat with the remaining pieces of chicken.
To the hot oil, add the onion and garlic and cook for 2 minutes. Add the carrot, celery, garlic, thyme, oregano, bay leaf and crushed red pepper. Cook for 10 minutes, stirring often so it doesn't burn.
Pour the whole tomatoes into a bowl and crush with 2 forks. Add the tomatoes to the vegetables and add the can of tomato puree.
Add the wine, taste and add the remaining salt and pepper.
Add the chicken back into the pot, reduce heat and cover. Simmer for 45 minutes to an hour, turning the pieces occasionally. Remove and discard the bay leaf. Skim off any excess fat.
Stir in the parsley and serve over pasta on individual plates. Top with freshly grated parmesan cheese.
If using a crockpot, after step 6, put everything into your slow cooker and set on low for 7-8 hours or on high for 3-4 hours. Sprinkle with fresh parsley and serve over fresh pasta and top with freshly grated parmesan cheese. Enjoy!