I've been here 6 months and he's been here 1. He has less experience, less schooling, and less qualifications than me. I'm wondering what steps I can take to renegotiate my salary to something closer to what he's making? I'm in Wisconsin and we're an at-will state, so I have to tread lightly or I can lose my job. My other coworkers are in the same situation, making the same as me with a $6k difference. (In addition, my coworker who just got a raise has been here 2 years and still makes $4.5k less than the new hire, with more qualifications).
I'm updating my resume tonight and looking into unions in the sector as well as possibly scheduling a walkout, and I have a meeting with HR on Thursday with at least 2 of my coworkers to back me up.
Any advice, legal or not, would be much appreciated.