Yarns which are Certified Organic are spun from fibre which is produced without the use of man-made chemicals such as herbicides, pesticides or chemical fertiliser.
When this fibre comes from an animal, the animal must be fed organic feed and raised under organic standards. This means that the wool comes from sheep that have been allowed to roam and graze. Additionally, the majority of the sheeps' diet must come from grazing for their wool to be considered organic. Animals used for organic yarn are kept in more humane conditions than those on factory farms.
If a yarn is GOTS ( Global Organic Textile Standard) Certified, the spinning process is also tightly controlled.