Preheat the oven to 350 degrees F. Heat the olive oil in a medium saute pan. Add the onions, thyme, salt, and pepper and cook over medium-low heat, stirring occasionally, for 8 to 10 minutes, until the onions are translucent but not brown. Off the heat, add the Worcestershire sauce, chicken stock, and tomato paste. Allow to cool slightly. In a large bowl, combine the ground chuck, onion mixture, bread crumbs, and eggs, and mix lightly with a fork. Don't mash or the meatloaf will be dense. Divide the mixture into 6 (10 to 11-ounce) portions and shape each portion into a small loaf on a sheet pan. Spread about a tablespoon of ketchup on the top of each portion. Bake for 40 to 45 minutes, until the internal temperature is 155 to 160 degrees F and the meat loaves are cooked through. Serve hot.