Place the boneless, skinless chicken breasts in the bottom of a slow cooker.
Pour the buffalo sauce evenly over the chicken.
Add the ranch dressing on top of the chicken and sauce.
Scatter the cubed cream cheese evenly over the mixture.
Cover and cook on low for 3 hours, or until the chicken is fully cooked and shreds easily.
Use two forks to shred the chicken directly in the slow cooker.
Stir the shredded chicken into the sauce and softened cream cheese until smooth.
Add the shredded cheddar cheese and stir until fully melted and combined.
Stir in the blue cheese crumbles if using.
Switch the slow cooker to the warm setting and serve directly from the crockpot.