Bronzeager, it is generally loose, with the other greens like chard, endive, etc. Sometimes stores are bad with the labelling, so look for a tough curly green bunch.
If none of your nearby stores carry it, ask the produce manager. They can and do respond to customer requests.
It isn't trendy, exactly, although it is getty more attention than before. It is planted very early in the spring, and seems to be available most of the year where I live (Philadelphia.)
Baby #3 born 12/6/2014. Working hard and nursing towards my goals!
Goal 1: No longer obese - 185lbs: Reached 12/19/14!
Goal 2: Normal BMI - 154lbs
Final Goal: 140lbs