The term crest typically refers to a ball of feathers on the heads of some breeds of chickens and waterfowl forming as part of a rounded protuberance or bulge on the skull.
Figure 1. Female (left) and male (right) Polish chickens. Source: Jacquie Jacob, University of Kentucky.
Figure 2. Crested duck. Source: Jacquie Jacob, University of Kentucky,
This is where you can find research-based information from America's land-grant universities enabled by eXtension.org
This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.