Ideally, Casey St. Clair would be spending Thanksgiving relaxing and eating dinner with her boyfriend and his family.

Instead, the part-time Target employee and substitute teacher will work next Thursday night during the early kickoff of the big-box retailer's Black Friday sale. Stores will open at 9 p.m. on Thanksgiving this year, reflecting a wider shift in the retail industry toward getting a head start on the biggest shopping day of the year.