Cook chicken breasts in slow cooker on low for 6-8 hours.
Cook orzo according to package directions until about half way done. Drain and set aside.
Heat olive oil in a large Dutch oven. Sauté onion and carrots until just tender 4-5 minutes. Then add in garlic and scallions, and cook for another 1-2 minutes. Sprinkle with ranch mix and stir to combine.
Add chicken broth, buffalo sauce, cheddar, parmesan and shredded chicken. Stir to combine and bring to a simmer. Reduce heat and simmer for 5 minutes, then add in the orzo and bring soup to a boil, stirring frequently until orzo is al dente.
Serve with sliced scallions, additional cilantro and blue cheese crumbles.