Ridley was incorporated and listed on the Australian Stock Exchange in 1987. At the time, the company's principal activities included the Diamond Salt operation and subsequently, interests in regional radio stations in Victoria.

In 1990, Ridley began the first stage of its transformation into Australia's largest stockfeed and salt company. This involved the acquisition of Barastoc Stockfeeds in 1990, the sale of its radio and certain property interests in 1991, and the acquisition of the Cheetham Salt and Cheetham Rural businesses in 1992. As part of the acquisitions, the vendors became strategic shareholders in the company. These shareholdings were sold in 1993 through the placement of shares to a wide range of private and institutional investors.

Since 1992, Ridley has undertaken a number of smaller acquisitions in Australia to expand its stockfeed operations. The acquisition of Cheetham and its integration with the original Diamond Salt operation generated significant synergies and enabled the enlarged salt business to expand by purchasing 50% Dominion Salt, New Zealand's major salt company, in 1996.

Ridley entered the North American market in 1994 by acquiring Feed-Rite, a large Canadian stockfeed company based in western Canada. In 1997 Ridley acquired Hubbard Feeds, based in the US mid-west, and listed Ridley Canada (now Ridley Inc) on the Toronto Stock Exchange. The acquisition of Hubbard Feeds almost doubled Ridley's North American stockfeed sales volume and included the low moisture block business.

In 1998 Ridley acquired Cotswold Pig Development Company Ltd in the UK. Cotswold developed and sold swine genetics in the UK and Europe. This business was sold in 2002 after a period of losses due to disease outbreaks.

Ridley acquired Wayne Feeds in 2000 substantially expanding its presence in the US stockfeed market and in 2004 the business and assets of Sweetlix LLC was acquired making Ridley the largest manufacturer of free choice feed supplement blocks in North America.

In 2005, Ridley acquired Dry Creek salt field in South Australia from Penrice for A$54.5m. The salt field is located on the outskirts of Adelaide and covers an area of 4,000 hectares with an annual production capacity of 650,000 tonnes. The salt field will become part of the operations of Ridley's wholly-owned subsidiary Cheetham Salt. In conjunction with the acquisition, Ridley has entered into a long term 'take or pay' contract to supply Penrice with approximately 600,000 tonnes of salt per annum via a dedicated brine pipeline. The duration of the contract is for an initial term of fourteen years, with Penrice having the option to renew the contract under the same terms at the end of the initial term for a further period of up to fourteen years. The 'take or pay' supply contract associated with this acquisition will provide an additional long-term stable income stream to Ridley's earnings.

In 2008 Ridley decided to pursue the sale of the Company’s 69% owned Canadian listed subsidiary, Ridley Inc.  Whilst the Company believed there were attractive industry rationalization opportunities available for Ridley Inc, which had the potential to create shareholder value, it was difficult for Ridley Corporation to support and facilitate these opportunities in a funding and strategic sense.  The sale was completed on 5 November to Fairfax Financial Holdings Limited.  The net sales proceeds of approximately $83m will be used to reduce debt.

2008

• Ridley sold it’s 69% share in Ridley Inc

2005

• Ridley acquired Dry Creek salt field in South Australia from Penrice

2004

• Acquired the assets of the livestock feed supplement business of Sweetlix. This will make Ridley Inc one of the largest manufacturers of free choice feed supplement blocks in North America
• Close down of Cotswold North America completed

2003

• Acquired Heartlands Inc a stockfeed manufacturer in North Dakota USA
• Opened a Cheetham Salt sales office in Japan

2002

• Acquired McCauley Bros, a manufacturer of premium quality equine feeds and nutritional supplements in the US
• Sold the Cotswold International-Europe swine genetics business

2000

• Acquired Wayne Feeds, one of the largest commercial feed manufacturers in the US
• Establishment of PT Garam a salt refiner in Indonesia

1998

• Acquired PM Ag Products, a low moisture block business in the US
• Acquired Macleod Feed Mill, based in Fort Macleod, Alberta, Canada
• Acquired Gringer Feed and Grain, a concentrate and complete feeds business in Iowa, USA

1997

• Acquired Hubbard Milling, a very significant presence in the US stockfeed market and largest manufacturer of low moisture supplement feed blocks
• Initial Public Offering of Ridley Canada on the Toronto Stock Exchange and subsequent name change to Ridley Inc
• Acquired Daco Laboratories Ltd premix plants in Lethbridge, Alberta and Winnipeg, Manitoba, Canada
• Acquired a further six stockfeed mills and a premix plant from Farmstock Stockfeed in Queensland, Australia
• Acquired Moloney's Stockfeed in Western district and Maffra Stockfeed in east Gippsland, Victoria, Australia

1996

• Acquired Zip Feeds a stockfeed business based in North and South Dakota, USA
• Acquired 50% share of Dominion Salt, a premier salt company in New Zealand
• Acquired Green Valley Feed Service feed mill and farm supply store in south-eastern Manitoba, Canada
• Acquired Farmix a manufacturer of premix products based in Mitchell, Ontario, Canada

1995

• Acquired Quality Feeds Alberta feed mill in Lacombe, Alberta, Canada

1994

• Acquired Feed-Rite a large stockfeed company based in the western provinces of Canada

1992

• Acquired Cheetham Salt and Cheetham Rural in Australia from the National Foods Limited Group

1990

• Acquired Milling Industries, Allied Mills and Fielders from Goodman Fielder Wattie, a national stockfeed business in Australia