Place the bacon on a foil-lined rimmed baking sheet. Put in the oven and turn the heat up to 400°F. Cook until crispy, about 20 minutes (do not let them overcook). Remove from oven and drain bacon on paper towels.
While the bacon is cooking, place the chicken breasts in a bowl and toss to coat with the avocado oil, salt, and pepper. Heat a griddle or skillet over medium-high heat. When hot, add the chicken breasts and cook until no longer pink, turning as needed. Remove from skillet and let sit for at least 5 minutes before slicing.
Divide the chopped romaine and the baby spinach evenly between 4 bowls. Slice the chicken breasts and divide them evenly between the 4 bowls, layering them across the center of the greens.
Arrange the sliced eggs on one side of the chicken, and the diced avocados on the other side of the chicken.
Dice the bacon and add it next to the avocados and arrange the halved tomatoes next to the sliced eggs.
Top with some blue cheese dressing (or dairy-free Ranch Dressing for Whole30 compliance) and eat right away.