The store have been closed more than 24 hours, which means that they have meat and produce that won't be as fresh. The meat is getting that much closer to the best before date. A lot of stores mark their meat and produce down to about 50% off the original price! As long as you take it home and freeze it or use it that day it's still great!
Some stores do this the night before a holiday towards closing. You just have to know your store and see when it happens. I know here on the Island, after Christmas when the stores go back to being closed on Sundays (YEAH!!!) that Monday morning is my favourite time to shop so I can get the markdowns. The meat counter is the first place I head to early in the morning. LOVE A DEAL!!
Enjoy your day.