Heat olive oil in a large saute pan over medium heat. Add onions, carrots, celery and mushrooms and cook until vegetables are soft, about 10 minutes. Add Worcestershire sauce, salt, and pepper and mix well. Remove from heat and let cool.
In a large bowl, gently scramble eggs. Add bread crumbs and parsley and stir well. Add cooled vegetable mixture and chicken meat and stir until well combined.
Pour mixture into greased pan and smooth the top. Cover surface with a thin layer of ketchup.
Place in oven and cook for an hour.
Recipe by Three Hungry Boys at https://www.threehungryboys.com/2022/11/15/chicken-meatloaf/