Which part of the rabbit is primarily assessed for muscle development during judging?

The hindquarters of the rabbit are primarily assessed for muscle development during judging because they are crucial for the animal's overall strength and movement. In rabbits, robust hindquarters indicate good genetics, health, and the ability to perform the activities necessary for their breed, such as jumping or running. Strong hindquarters provide a solid foundation for the animal's body and contribute significantly to its overall conformation, making them a focal point in judging criteria.

While other parts such as the forequarters and back also hold importance in terms of overall structure and balance, it's the hindquarters that are particularly indicative of muscle development, as they house larger muscle groups that are essential for mobility and agility in rabbits. The head, while being a critical element of breed identification and type, does not directly reflect muscle development in the same way.