What characteristic defines an 'ewe neck'?

The characteristic that defines an 'ewe neck' is indeed a short neck with a convex shape. Ewe necks are commonly observed in horses that have a less muscular and athletic appearance. This type of neck is often seen as a conformation flaw because it can indicate a lack of strength and an overall poor quality of neck structure in terms of riding performance.

In contrast, other neck types, such as a long, straight neck or a muscular neck with a strong build, are typically considered desirable for athletic horses, as they contribute to balance and mobility. A thick and short neck, while it may seem similar to an 'ewe neck,' usually describes a different issue regarding conformation and muscle structure and does not emphasize the convex shape that defines an 'ewe neck.' Therefore, identifying the correct characteristic of 'ewe neck' is vital for understanding equine conformation and its implications for performance.