Variability within the specific breed of sheep, goat or camelids

The most common breeds used in felting are sheep and alpaca, but llama, guanaca, cashmere (goat), angora (goat or rabbit) and some camel will also felt. However, given a single breed of animal, often sheep, the felting ability may differ greatly. I will use the term sheep to refer to all mostly.

If the sheep is not explicitly raised for wool quality as is the case int dual use sheep, the wool quality may differ from sheep to sheep. The domestication process is based on selection of animals for breeding of different traits and allowing for genetic diversity to produce healthy animals. All these impact the quality of the wool within a breed.

Some breeds have national and international registry, allowing for the breed to be classified based on some uniform criteria (such as in Shetland). However, even for these breeds, we do not have a good way to check whether wool roving sold as breed X exhibits the main characteristics of this breed. Well-selling breeds like tend to be over used as brand, attributed to sheep that are only partially of this breed.

Some breeds are known to have variable wool quality within a single sheep. A well-known example of this is llama where the wool quality varies from very fine to very coarse depending on the area of the animal wool comes from (See [2]). Some primitive sheep breeds, those with genetic ancestry that goes all the way back to pre-historic times also have this property. The common way to approach this is to mix wool from many animals to get an average wool quality.

Finally, the age, well-being and nutrition of the animal has a big impact on the wool quality. The younger animals generally have finer wool that is easier to felt and produces denser felt. As the animal ages, wool tends to get coarser and in some breeds, harder to felt. Conditions that stress the animal may produce weak wool that may have breakages. This may result in weaker and more hairy felt depending on the ultimate use.

Interestingly some sheep that produce very curly wool like Gotland may produce more or less straight winter coat (Personal correspondence, Kim Goodling, Vermont Grandview Farm ). This impacts the potential uses of the wool as well.