chicken scratch

Over on the vintage apron flickr group the history of chicken scratch came up. Why is it called chicken scratch? Chicken scratch embroidery is when X's and other shapes (stars, crosses, O's, etc.) are embroidered onto gingham to make this super cool lacy look. All types of projects can be made with chicken scratch needlework but I usually see the techniques used on aprons, and I love it so much. There's a wonderful tutorial here if you want to try it out.

Does anyone know more about the history of this technique and why it is called chicken scratch?