Cook the bacon over medium heat in a skillet, preferably cast iron. Once it's crisped to your liking, remove the bacon and place on a paper towel to drain. Reserve the rendered fat. Once cooled, cut the bacon into bite-size pieces.
Set a large skillet over medium heat and add the reserved rendered bacon fat. Add the ciabatta and cook, stirring frequently, until the bread is nicely browned and crisped all over. Set the croutons aside.
Bring a pot of water to a boil. Add the eggs and reduce the heat to a simmer. Cook the eggs for 8 minutes. Using a slotted spoon, remove and place the eggs into an ice bath. When cool enough to handle, peel the eggs and cut them in half.
Add the mixed greens to a serving bowl and dress to your liking with your favorite vinaigrette. Add the bacon, croutons, eggs, and avocado. Serve at once.