not good for chicken legs. It's pretty big... someone with thin legs might not be able to actually attach it, and with how the attachments work, it doesn't like to wrap around small cylinders.
That being said, if you can get it on your leg, it holds securely (there's rubber grip stuff put onto the inside of the straps) and holds plenty of weight (I've used it to hold a 1911, 4 mags for it, a plastic grenade (filled with bb's, weighed in around 1.5lbs), and 4 metal VN style hicaps). I liked mine for a long time while I used it.
If you have never used a leg rig of any kind before, I would recommend trying someone's before you buy one. They aren't for everybody.