Stonyfield Farm, also simply called Stonyfield, is an organic yogurt maker located in Londonderry, New Hampshire, USA. Stonyfield Farm was founded by Samuel Kaymen in 1983, on a 19th-century farmstead in Wilton, New Hampshire, as an organic farming school. The company makes the number-one selling brand of organic yogurt and number-three overall yogurt brand in the United States, according to Fortune magazine. It owns brands including YoBaby, YoToddler, YoKids and Oikos. In 2001, Groupe Danone, a French food product company whose brands include Evian bottled water and Danone/Dannon yogurt, purchased an initial 40% of Stonyfield shares. This was followed in late 2003 with an additional purchase such that Group Danone now owns about 85% of Stonyfield shares. Gary Hirshberg is chairman and former president and CEO of Stonyfield Farm.