A Data-Man 7500 (Cognex Corporation, Natick, USA) barcode reader was selected for the experiment (Fig. 3), as the surface, the colour and further characteristics such as the curvature of the beak and the skin of a chicken body part, aswell as the features of a computer screen, disagree with the usual reading environment of a commercial offthe-shelf barcode reader, which is for the most part composed of a dark barcode-symbol on a white background, printed on an even surface.