No doubt the distinction between street art and graffiti is clear to you. I find labels very blurry. Is the difference related to the artistic quality? i.e. is the good stuff "street art" and the lesser quality "graffiti"? Is one with a brush and the other with a spray can? Is "street art" legal but graffiti clandestine? Can it be 3-D as well as 2-D?The idea of creating a thread for street art was to separate it from graffiti, scribblings on a wall. I have no problems with your chicken, but a commercial sign or ad is usually not considered as art. But today I would not be surprised if somebody hauled a hot dog sign into a gallery and called it art.
Here is an example of street art made from junk.