That looks very similar to what I have! (Mine is pink though.) It's adjustable, so if it's too big or too small, you can readjust it. Before buying it, I would check to see if there is measurements on it and measure your hen to be sure it's not too small.
I have a harness that doesn't press the crop that works well for my birds. It's a very similar design to this one on Amazon, though I highly doubt it costed as much. (The one below is like $54, but mine might have costed $10-$20, and came with a leash.) Hopefully you can find one that's a lot...