Better yet, If I owned a fast food joint, I would close down Friday and Saturday. Just tell the strikers, no work for you those days. Screw them. Starve them out. Go find work elsewhere. Rots of ruck with that in the new Obama economy. Then hire strike busters and shove the trouble makers out.
In a at will state for sure, and probably elsewhere, not showing up for work or impeding the business is grounds for dismissal. I don’t believe not performing your job because you were protesting your employer is a valid excuse for missing work. So fire them for cause and dispute any unemployment claim.