I have done alot of agency over the past 20 + years, and the 'norm' is working every other weekend, though one place had staf working 2 weekends on, one off. Where I am now, it's every other weekend.
The job before this one, LPN's and CNA's are Union. It didn't really help too much, as the owner dragged butt on the contract for over 2 years. Guess what got ratified 1 1/2 months before I took my RN boards?!