Step 1) Preheat oven to 350 degrees. In medium size saucepan, bring the tomatoes, tomato juice, green pepper, onion, garlic, salt, black pepper, and oregano to a boil over medium heat. Reduce the heat to low, cover, and simmer, stirring occasionally, until thickened - approximately 25 minutes.
Step 2) Meanwhile, place each chicken breast between two sheets of wax paper and gently pound to a 1/4 inch thickness with meat mallet or rolling pin.
Step 3) In a small bowl, combine the cottage cheese, egg yolk, parsley, and Parmesan cheese. Spread 1 tablespoon (approximately) of the mixture in the center of each chicken piece, leaving a 1/2 inch border all around. Roll up and set aside.
Step 4) Spoon half the tomato sauce into an 8 inch pie plate or baking dish. Arrange the chicken rolls on top, seam sides down. Pour the remaining tomato sauce over them and sprinkle with the shredded Mozzarella cheese.
** At this point if you want, the chicken rolls can be stored. Cover with plastic wrap and refrigerate for up to 6 hours.
Bake uncovered for 40-45 minutes at 350 degrees or until the chicken is cooked through. Set one roll on each dinner plate and spoon some of the sauce over it.