Which of the following methods can be used to identify sheep?

Ear tagging is a widely used method for identifying sheep due to its practicality, efficiency, and effectiveness in a flock management context. This method involves placing a small, numbered tag in the ear of the sheep, which makes it easy for handlers to visually identify each animal from a distance. Tags can be made from durable materials that withstand outdoor conditions, and they can include unique identification numbers or codes that help track individual sheep for breeding, health management, and record-keeping purposes.

Microchipping, while a reliable identification method used in other animals, is less common in sheep due to the invasive nature of the process and the cost involved compared to ear tagging. Branding can be used, but it is often less favored in sheep management because the procedures can be more stressful for the animals and the identification can become less clear as the wool grows. Collar identification might also be used, but it is not as practical since collars can be easily lost or removed and can pose a risk of injury if not properly managed. Ear tagging combines visibility, ease of implementation, and low stress for the animals, making it the preferred choice for sheep identification.