How is the age of a sheep typically determined?

The age of a sheep is typically determined by examining its teeth, specifically by looking at the wear and development of the incisors. As sheep mature, they go through distinct stages of dental development, which is consistent and predictable. Young sheep have a full set of baby teeth, which eventually are replaced by permanent incisors. This process occurs at specific ages, which allows for an accurate estimation of the sheep's age.

For example, by the age of 1 year, a sheep usually has two permanent incisors; at 2 years, four; and by 3 years, they typically have six. After that, the wear on the teeth can provide further clues about age, as older sheep may exhibit more wear or loss of teeth. This method is reliable and used widely in the livestock industry for assessing age and making management decisions regarding breeding and culling.

Other methods mentioned, such as examining horns or ribs, may not provide accurate age conclusions and can vary significantly among different breeds or individuals, making them less reliable. Observing wool quality is also not a direct indicator of age as it can change due to a variety of factors unrelated to the sheep's age.