Place chicken in a 1-1/2- or 3-quart slow cooker.
Top with wing sauce, butter, and ranch dressing mix.
Cook, covered, on low for 2-1/2 to 3 hours; check to ensure chicken reaches an internal temp of 165°F.
Remove chicken and shred with two forks.
Reserve 1/3 cup of the cooking juices; discard the rest.
Return shredded chicken and reserved juices to the slow cooker to keep warm.
In a serving dish, arrange romaine salad mix.
Top with chicken, julienned carrot, avocado, and blue cheese.
Drizzle generously with blue cheese dressing and serve immediately.
