ELI5: Why meat, like chicken and turkey breasts are dramatically less expensive from my butcher than they are if bought a big brand super market?

If I go to a Stop and Stop, Keyfood, Wegmans, Associated or Shop rite chicken thighs run about 1.29$/lb or a whole chicken is on sale for about 99c/lb, while ground chicken or turkey is almost 6-7$ a pound and if I'd like chicken breast it's about 3-4$/lb and forget even finding turkey outside of thanksgiving.

But, if I visit my butcher, I can get ground chicken at 1.99/lb, breasts of better quality for 2.99$/lb and even Turkey breast ground or fresh for about 2 and change.

Why the price disparity?

bon appetit